Encyclopedia of Life Support Systems (UNESCO-EOLSS)



6.147.4

SEXUAL BEHAVIOR AND REPRODUCTIVE HEALTH

Elwood D. Carlson

Center for Demography & Population Health, Florida State University, USA

(E. Carlson is Charles B. Nam Professor in Sociology of Population and a faculty associate of the Center for Demography and Population Health at Florida State University. He previously led the research group on reproductive health at the Max Planck Institute for Demographic Research in Rostock, Germany. He holds a PhD in Sociology from the University of California at Berkeley.)

(10,000 words)

Keywords

Sexual behavior, reproductive health, menarche, menopause, infertility, sexual dysfunction, maternal mortality, low birth weight, prematurity, HIV/AIDS, sexually transmitted infection, age at first intercourse, birth intervals, postpartum abstinence, postpartum amenorrhea, sexual violence.

Contents

1. Effects of Health on Sexual Behavior

1.1. Menarche and Menopause in Societal Context

1.2. Health Limitations on Sexual Activity

1.2.1. Age Effects

1.2.2. Disease and Disability as Limitations of Sexual Activity

1.2.3. Behavioral Complications

1.2.4. Medical and Pharmacological Treatments

2. Effects of Sexual Behavior on Reproductive Health

2.1. Sexual Behavior and Adverse Birth Outcomes

2.1.1. Age at First Intercourse, Age at Conception and Infant Outcomes

2.1.2. Sexual Behavior, Birth Interval, and Infant Outcomes

2.1.3. Sexually Transmitted Infections and Adverse Birth Outcomes

2.2. Sexual Behavior and Reproductive Impairment

2.2.1. Reproductive Consequences of Sexually Transmitted Infections

2.2.2. Secondary Sterility

2.2.3. Elective Sterilization

2.3. Sexual Behavior, Reproductive Health and Mortality

2.3.1. Sexual Behavior and Disease-Related Mortality

2.3.2. Maternal Mortality

2.4. Health Impact of Violent Sexual Behavior

2.4.1. Social Crisis and Organized Sexual Violence

2.4.2. Violence in Early Life and Reproductive Health

2.4.3. Violence in Adulthood and Reproductive Health

Summary

Reproductive health includes factors that influence the ability of men and women to produce healthy offspring. Just as health may influence sexual behavior and reproduction, sexual behavior may have a reciprocal impact on health. Health limitations on sexual activity include age effects, disease and disability as limitations of sexual activity, behavioral complications, and effects of medical treatment. Effects of sexual behavior on reproductive health include adverse pregnancy outcomes (spontaneous loss, prematurity and low birth weight) as affected by timing of sexual activity, number of sexual partners, and sexually transmitted disease. Other effects include reproductive impairment, either involuntarily as the result of disease or complications of pregnancy and delivery or voluntarily in the case of sterilization, as well as possible disease and death of adults as a result of sexual behavior. Violent sexual behavior has powerful effects on reproductive health, whether it is experienced early in life or in adulthood, and whether it occurs systematically as in wars and other social upheavals or as hidden deviance involving isolated individuals.

SEXUAL BEHAVIOR AND REPRODUCTIVE HEALTH

A widely-accepted definition of reproductive health emerged from the International Conference on Population and Development, organized in Cairo in 1994 by the United Nations. At the Cairo conference, reproductive health was defined as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity, in all matters relating to the reproductive system and to its functions and processes. Reproductive health therefore implies that people are able to have a satisfying and safe sex life and that they have the capability to reproduce and the freedom to decide if, when and how often to do so. Implicit in this last condition are the right of men and women to be informed and to have access to safe, effective, affordable and acceptable methods of family planning of their choice, as well as other methods of their choice for regulation of fertility which are not against the law, and the right of access to appropriate health-care services that will enable women to go safely through pregnancy and childbirth and provide couples with the best chance of having a healthy infant. In line with the above definition of reproductive health, reproductive health care is defined as the constellation of methods, techniques and services that contribute to reproductive health and well-being by preventing and solving reproductive health problems. It also includes sexual health, the purpose of which is the enhancement of life and personal relations, and not merely counseling and care related to reproduction and sexually transmitted diseases.”

Reproductive health includes factors that influence the ability of men and women to produce healthy offspring. Though all health conditions may influence this ability, here attention centers on economic and social variations in human societies that may influence sexual behavior and reproduction (to the extent that they produce observable demographic consequences in populations) and that may influence variations in the health of mothers and infants during gestation and childbirth. Just as health may influence sexual behavior and reproduction, sexual behavior may have a reciprocal impact on health.

1. Effects of Health on Sexual Behavior

Human physiology imposes constraints on reproductive behavior. For example, humans become capable of reproduction only at puberty, and women do not bear children following menopause. Social and cultural contexts, by affecting health, also can affect the timing of puberty and menopause as physiological limits on reproduction. Health limitations in adulthood, also systematically related to social position, can have further systematic effects on sexual behavior. All of these physiological dimensions of reproductive health are affected by social organization, custom and standards of living, so that health serves as a conduit for transmitting such social variations into consequences for sexual behavior.

1.1. Menarche and Menopause in Societal Context

The physiological onset of menarche marks the beginning of reproductive capacity in women. Both onset of menarche and the parallel but less-studied beginning of reproductive capacity in men are influenced by nutrition, level of physical activity, and other factors which in turn depend on social organization. The age of menarche has declined in many modern populations as nutritional improvements have produced healthier and earlier maturation. Earlier menarche therefore usually is taken as an outcome or indicator of improvements in the health of children and young adults. However, scientists also recognize that health problems such as obesity or exposure to chemicals artificially introduced into the environment may also affect this timing. The earlier age at menarche also has possible negative implications for reproductive health, because until the recent trend toward earlier onset in the most developed countries, menarche usually occurred at ages around 15 to 17 when women were more physiologically mature. Menarche at an average age of 13, commonly observed in the most advanced urban industrial nations today, raises new issues of reproductive health risks for the earliest conceptions that may occur at such young ages.

Physical activity has been demonstrated to affect menarche, and different cultures organize different levels of such activity for women. For example, young girls who engage in strenuous physical activity combined with diet limitation, such as young ballet dancers or gymnasts, can exhibit delayed onset of menarche (Fujii & Demura 2005, Castello-Branco et al 2006). Both intensity of physical activity and dietary restrictions have been documented as independent influences on this delay. Research (Matchock & Sussman 2006) also suggests that timing of menarche may be influenced by factors such as absence of fathers, presence of older sisters, and other household compositional effects that may indicate pheromonal effects, although such interpretations are hotly debated by other researchers (Mendle et al 2006) who suggest selection rather than causal effects.

The ability to conceive a pregnancy declines with age for women and ends at menopause. Menopause occurs, on average, near the end of the fifth decade of life for women in urban industrial nations, and very tentative evidence suggests that this biological boundary also may have shifted slightly in response to better nutrition and health care over the past century or two. Reported ages at menopause do appear to be slightly younger on average (early to mid-40s) for women in developing societies. While few behavioral or social factors have been linked to systematic variations in menopause, it does appear that smoking is linked to slightly earlier menopause than observed among non-smoking women. For men the physiological capacity to reproduce has no clear upper age limit but does decline during late adulthood. Studies also indicate that the sex drive impelling men to fulfill their potential for reproduction also declines with age, in fact beginning in early adulthood and lowering libidinal energies steadily throughout the remainder of life.

In addition to limitations on reproductive ability specifically linked to sexual behavior (explored in section 2 below) a number of other behavioral and lifestyle factors can alter the ability of men and women to reproduce. Young women who suffer from anorexia nervosa, for example, can experience amenorrhea and related subfecundity. More general social conditions also can exert reproductive health effects similar to such individualized conditions. The best-documented example of such societal-level effects occurred in the Netherlands during the Second World War in the twentieth century, which produced what become known as the Dutch Hunger Winter. Food shortages led to widespread reports by physicians that their female patients experienced famine amenorrhea, a temporary cessation of the menses and the ovulatory cycle as these women’s bodies spontaneously gave priority to maintenance of the existing organism over the potential to reproduce. However, comparison of this acute famine episode during wartime to chronic famine conditions in other parts of the world led researchers to conclude that famine amenorrhea appears to be a temporary physiological reaction. Women who live for extended periods of time (decades or even generations) under conditions of chronic malnutrition even approaching famine experience eventual physiological adaptation. Their bodies manage to resume and maintain the ovulatory/menstrual cycle, although perhaps at a reduced level of reproductive efficiency.

1.2. Health Limitations on Sexual Activity

In addition to direct effects on the ability to conceive and reproduce, other aspects of health can influence reproduction by affecting the desire and/or ability of men and women to engage in sexual activity. Adverse health conditions can impair sexual function during the reproductive ages, and can be arranged in several broad categories: age effects, disease and disability as limitations on sexual activity, behavioral complications, and consequences of medical and pharmacological treatment.

1.2.1. Age effects

Age-related variations in sexual activity have long been described, but the extent to which such patterns actually result from physiological processes intrinsically linked to aging of human organisms remains poorly understood. Most proximate features of sexual activity, including erectile dysfunction in men, vaginal dryness in women and many other aspects of sexual functioning, have been shown in a vast research literature to become increasingly serious problems with increasing age. However, as with many other health complications of increasing age, the extent to which each specific problem is actually due to physiological aging must be disentangled from the behavioral and attitudinal shifts that people learn to expect as part of the aging process. For example, declining physical exercise with advancing age is regarded in many if not most cultures as normal, constituting a fine example of what Matilda White Riley meant when she described old age as enforced deviance. Since lack of physical exercise has been strongly linked to many health outcomes (including sexual dysfunction) at least some significant part of what are conventionally measured as “aging” effects on sexual activity and libido may in fact be societally-conditioned by-products of socially-sanctioned age roles. Age-appropriate behavior varies across cultures, and involves diet, patterns of social interaction, and other related factors that have direct bearing on sexual activity, including the appropriateness of sexual activity itself.

1.2.2. Disease and Disability as Limitations of Sexual Activity

Endocrine disorders can affect sexual functioning, and so also reproductive health. In males, diabetes can impair erectile function, and for both males and females is linked to depression and related sexual dysfunction. Since risk factors for diabetes vary within social categories of any population, this and other endocrine disorders provide another possible link through which social structure can affect sexual activity through health. Although declining testosterone production with age in men and variability in the (much lower) testosterone levels in women is sometimes believed to be related to reduced sexual desire and activity, clear medical evidence on this point awaits further research. Estrogen deficiencies in women have clear physiological consequences including vaginal dryness and pain associated with vaginal intercourse. Other endocrine disorders possibly linked to sexual function include adrenal and thyroid function. Neurological disorders have obvious implications for sexual function and reproductive health. Spinal cord injuries and nerve damage such as may result from automobile injuries, accidental falls, athletic and other physical activity (including abuse and violence), and a range of other socially-conditioned events can have profound effects on sexual function. Epilepsy, multiple sclerosis, Parkinson’s disease, and similar neurological diseases can both affect physiological sexual functioning and disrupt the mental and emotional processes involved in satisfactory sexual relationships. Circulatory disorders are directly implicated in male erectile dysfunction. The existence of conditions such as coronary artery disease also can create fears that sexual activity might lead to myocardial infarction or other circulatory system incidents. While kidney disease is not strictly a circulatory disorder, the anemia often produced by renal problems can result in fatigue, uremia, and disturbance of reproductive hormones, and has been linked to atherosclerosis which can have further effects on libido and sexual functioning. Digestive/genito-urinary disorders often interfere directly with sexual function, as in the case of inflammatory diseases such as Crohn’s disease, ulcerative colitis, inflammatory pelvic disease, and other conditions producing pain and disruption of bodily functions including but not limited specifically to sexual activity. These conditions, often aggrevated by stressful social contexts and relationships, affect large proportions of both men and women in many contemporary societies and consequently have the potential for widespread impact on sexual health.

Psychological disorders form another vast realm of influences on sexual activity, worthy of entire volumes in their own right. Chief among these effects, however, we may identify depression as a psychological state, sometimes arising out of physiological problems such as those reviewed above and sometimes produced by other features of an individual’s social context and interactions and that individual’s own organic characteristics. Depression has been identified as both an outcome of and a precursor for some of the physiological disorders outlined above, and is implicated in many of the behavioral problems noted below, including obesity, alcohol consumption, and other activities that can affect sexual function. Anxiety and psychological stress constitute another important psychological pathway by which social and physiological factors can affect health, including sexual health, and since stress and anxiety have been shown to vary strongly across social contexts and groups, these pyschological states (like depression) can transmit differences in social position into health outcomes.

1.2.3. Behavioral complications

Even in the absence of immediate disease or injury, behaviors arising from many of the above conditions as well as from general lifestyle differences in populations can exacerbate sexual dysfunction, as in the case of fear of a heart attack that limits sexual activity for heart disease patients. Smoking offers the most well-documented behavioral effect on sexual health, both directly through its impact on physiological capacities and processes involved in satisfactory intercourse itself, and indirectly through health complications in many of the areas reviewed above. However, over-eating and obesity, other dietary irregularities such as vitamin deficiencies, alcohol abuse, drug dependence, and sedentary lifestyles that neglect physical exercise all have been implicated both directly as impacting sexual function and indirectly as affecting other aspects of health important for a healthy sex life.

1.2.4. Medical and pharmacological treatments

Treatments of other health conditions can themselves produce deleterious side effects for sexual functioning. Radiation therapy and chemotherapy for malignant neoplasms have drastic health side effects, including severe impairment of sexual activity particularly for (but not limited to) cancers of the reproductive system in both women and men. Many medications prescribed for reducing high blood pressure, cholesterol and other risk factors for circulatory diseases have side effects that include reduced libido, erectile disfunction in men, vaginal dryness for women, and other effects on sexual health. While surgery involving the genito-urinary system and related organs and systems of the body has witnessed rapid progress in recent years toward preserving sexual function after such procedures, direct consequences for sexual function still obviously remain for a substantial number of such patients. Antipsychotic medications traditionally also had severe side effects on sexual functioning, reducing libido and other aspects of sexual function (including sometimes inducing amenorrhea) for one-third to half of all patients, although new classes of such medications have shown promise in reducing these effects.

2. Effects of Sexual Behavior on Reproductive Health

Just as health status, influenced by social context, has important effects on sexual activity, sexual behavior has direct impacts on reproductive health. Variations in sexual behavior, influenced in many cases by societal context, can create or resolve reproductive health problems for both parents and infants. These problems include adverse birth outcomes for newborn infants, impairment of reproductive ability as a result of sexual behavior, and other health consequences of sexual activity for adults, sometimes even including death from sexually transmitted infections or violence.

2.1. Sexual Behavior and Adverse Birth Outcomes

While a wide range of factors can adversely affect the health of newborn infants during their particularly vulnerable period of the lifespan, certain factors relate directly to parental sexual behavior and the reproductive process itself and may be considered integral elements of reproductive health. These center on the social conventions that limit and direct sexual activity, including the timing of first intercourse and conception, the interval between pregnancies, and patterns of sexual partner selection with special emphasis on the risks entailed in interaction with multiple partners.

2.1.1. Age at First Intercourse, Age at Conception and Infant Outcomes

The age at which individuals first engage in sexual intercourse, and in consequence the age at which women first become pregnant and give birth, have been linked to health outcomes for women and for their children. Until the recent rejuvenation of the age of menarche (noted under health effects on sexual activity, above) age at conception generally had a direct correlation with the probability of many types of congenital fetal and birth abnormalities. Research has documented the tendency of congenital chromosomal and other abnormalities in infants to increase exponentially with the increasing age of both mothers and fathers independently. Although the effects of maternal age appear to be greater than the affects of paternal age, both are significant predictors of such adverse outcomes. In traditional societies where reproduction is widely encouraged and begins at an early age for most or all of the population, evidence suggests that the health of infants, including the incidence of congenital abnormalities, the frequency of pregnancy complications, and more generally the consequent probability of survival and good health in later life, is optimal for births to quite young mothers. Ages seventeen or eighteen have been suggested by some biologists as the probable optimum biological age for reproduction in such populations.

This underlying physiological pattern of early optimum age for reproduction becomes complicated, however, in contemporary developed societies featuring earlier menarche and also experiencing differentially delayed marriage and childbearing for different population strata. The key social complication arises because such delays occur more often for women with more social and economic advantages. More stable parental families, more parental economic resources, longer involvement in formal education, greater opportunities for personal economic advancement, and related advantages all encourage postponement of marriages and childbearing, so that women who have children at the youngest ages in such societies become a negatively-selected subpopulation of disadvantaged mothers. Not only does the younger age at menarche mean that the youngest mothers are more physiologically immature than in the past, but the negative social selection means that these youngest mothers also have poorer health themselves, fewer health resources for their children, and consequent poorer health outcomes for those children. Some scholars have even advanced a hypothesis that disadvantaged women are aware of the steeper declines in health that await them at older ages, and that this awareness actually has the paradoxical effect of reinforcing the tendency of such women toward accelerated reproduction at early ages, perhaps compounding the problem. These social complications of the underlying physiological age gradient in reproductive health are so strong that in many societies they greatly extend and magnify a j-shaped curve of the risk of adverse birth outcomes and actual infant death. Infants of the youngest (negatively-selected) mothers have greater risks of dying and greater risks of lifelong health complications when they survive infancy. After reaching the minimum level of risk around the modal age for reproduction, the underlying physiological pattern of health and survival risks rising with age reappears even in these populations, however, for the remainder of the reproductive ages.

2.1.2. Sexual Behavior, Length of Birth Interval and Infant Outcomes

After men and women have begun sexual activity, other variations in sexual behavior and customs continue to affect frequency and timing of such activity, with important consequences for infant outcomes. The length of inter-birth intervals are influenced by post-partum taboos on sexual intercourse, post-partum amenorrhea related to breastfeeding, deliberate contraception and other fertility control behaviors, and the length of these intervals constitutes one such variation strongly related to infant health and survival. When births occur in rapid succession, maternal depletion progressively reduces the physiological reserves and reproductive health of women, which in turn increases the risks of low birth weight, calcium and other deficiencies during pregnancy, and a wide range of related adverse effects on fetal and infant health. Safer birth intervals appear to result when births are spaced at least two years apart, with even greater benefits for children born three or four years apart. The apparent advantages of longer birth intervals do not extend to intervals longer than five years, but this probably represents the confounding of several distinct tendencies or effects all linked to duration between successive births. First, as noted above, adverse birth outcomes increase with increasing age of mothers (and fathers), and longer birth intervals invariably also involve older parents. Second, birth intervals longer than five years exhibit higher rates of maternal health complications such as preecclampsia, possibly due to selection effects that concentrate women with reproductive problems at these longer birth interval durations. These selection and age effects may conceal continued increases in purely duration-related benefits for birth intervals of even five or more years.

In traditional societies where localized, kin-based and religious customs exert important controls on sexual behavior, post-partum taboos on sexual intercourse furnish an important social mechanism for lengthening birth intervals. The duration of such taboos varies dramatically across societies that practice them, with the most prominent examples occurring in subsaharan Africa. In countries in closest cultural and geographic proximity to the Islamic societies of northern Africa (for example, in Mali, Niger and Senegal) the 40-day period of post-partum abstinence prescribed by that religion is widely observed. However, even longer traditional post-partum sexual taboos exist in many west African nations such as Ghana, Cameroon, Ivory Coast, Liberia or Togo, sometimes reaching two years or longer. These cultural traditions limiting sexual behavior were not as strong historically in eastern Africa, where post-partum taboos on intercourse lasted usually only a few months where they existed at all. Paradoxically, European colonial intervention in these traditional cultures (through urbanization, formalized education systems, individualization of economic activity and particularly the influence of the Catholic Church and other efforts to Christianize these populations) has tended to weaken and discourage post-partum sexual taboos. In eastern Africa these effects have been particularly strong, in some cases actually shortening the length of inter-birth intervals. In western Africa the duration of post-partum sexual abstinence and the extent of its practice have been shown in demographic and health surveys to be inversely correlated with education and negatively related to residence in urban areas.

Even in the absence of cultural practices such as post-partum sexual abstinence, breastfeeding of infants long has been known to postpone the resumption of the menstrual/ovulatory cycle for women following childbirth. This effect is most pronounced in the first few months immediately following birth, and attenuates rapidly at longer durations. The prevalence of breastfeeding also varies over time and across population strata within societies, and exhibits clear differentials between different cultures and levels of development. As with post-partum abstinence, breastfeeding has sometimes declined as a result of colonial penetration into traditional cultures. Women seeking to imitate “modern” colonial models of behavior have truncated or abandoned breastfeeding traditions in some settings, and encouragement by multinational corporations seeking to replace breast milk with sales of their infant formula products has in some periods and places played a highly controversial role in this process. However, even within developed societies popular attitudes about breastfeeding follow cyclic trends, so that clear generalizations about the long-term pattern in breastfeeding become very difficult to make. The contraceptive effects of breastfeeding do not play a significant role in fertility control behaviors in developed societies, where widespread patterns of other deliberate contraceptive behavior largely render these effects unimportant. In countries with substantial female labor force participation, breastfeeding also may be curtailed by or reduced by a woman’s return to the workplace.

Deliberate contraceptive practices (discussed more fully in the following chapter) provide the chief behavioral mechanism regulating sexual behavior in developed countries in order to affect the length of birth intervals. The specific methods of contraception adopted for this purpose vary widely across countries, with intrauterine devices constituting the most prevalent method for the world as a whole, but with chemical contraceptives such as the birth control pill playing a more significant role in specific societies such as the United States. Longer birth intervals as a result of such contraceptive practices contribute importantly to more advantageous birth outcomes observed among some subgroups of the population than among others, including greater proportions of pregnancies carried to full gestational term and resulting in normal birth weights. These advantages appear for women with higher levels of education, for those who are married compared to women bearing children outside marriage, and for some ethnic groups compared to others. Contraceptive practices and other aspects of family planning are discussed more fully in the next chapter of this volume.

2.1.3. Sexually Transmitted Infections and Adverse Fetal and Infant Outcomes

Sexually transmitted infections and bacterial vaginosis (see section 2.2.1. below) are directly implicated by an extensive body of medical research in the premature rupture of amniotic membranes (PROM) and associated premature labor and delivery of infants. Prematurity, given normal patterns of fetal growth, also tends to be accompanied by low birth weight. Both birth weight and gestational age at birth strongly predict infant survival as well as many features of adult health in later life. Sexually transmitted infections also appear to be precipitating factors in spontaneous abortions, affecting reproductive health during the fetal period as well as at birth and afterward. Syphilis increases the risk of late fetal deaths, which may occur in up to one-third of pregnancies for women with untreated syphilis. Herpes simplex virus, latent and nonlethal to adult hosts and transmitted in semen, vaginal fluids, or saliva, also may be transmitted in the birth canal during childbirth; infection may lead to brain damage and even infant death. Chlamydia can cause spontaneous abortion, premature rupture of amniotic membranes and premature birth, blindness as a result of conjunctivitis, or pneumonia.

2.1.4. Spontaneous and Induced Abortion and Determinants of Fetal Wastage

The incidence of spontaneous abortion (including all pregnancy wastage from the moment of conception through live birth, combining stillbirths and other fetal deaths) is not well-measured in any existing population, due largely to the difficulties of identifying pregnancies at very early gestational durations before they end in spontaneous losses. The result, for recorded pregnancies, appears to be a backward-bending curve of risk of fetal death at the earliest gestational ages. This backward-bending curve is a sure sign that early fetal losses are undercounted, since clinical research uniformly suggests a continuous exponential decline in the risk of fetal loss beginning at conception and continuing throughout pregnancy. The most recent clinical estimates suggest that between one-third and one-half of all conceptions end in spontaneous losses, many of them never recognized by women and often mistaken for menstrual “spotting” or mis-timed menstrual periods. This measurement difficulty means that patterns of fetal loss during the first trimester of pregnancy (up to twelve weeks following conception) and including a large majority of all fetal losses, remain very poorly understood in all populations everywhere in the world. For example, since most induced abortions also occur in this early period of pregnancy, any statistical rate expressing induced abortions as a proportion of all known pregnancies seriously distorts and overstates that proportion because a substantial fraction of the denominator (unrecognized spontaneous losses) is simply missing from the calculation.

Despite this severe limitation in our understanding of reproductive health patterns during gestation, considerably more is known about the second and third trimesters of pregnancy. The extremely low rate of fetal losses found for very young women (15 to 17 years old) supports the notion advanced in 2.1.1. above of a very early biologically optimum age for reproduction. The rising risk of fetal death with ages of women mirrors the rising risks of adverse outcomes observed after birth. As for adverse birth outcomes, risks of fetal death are lower for women who are married than for those who are unmarried, and decline with more educational attainment and more economic stability.

Social differences in risk of spontaneous loss appear most strongly during the second trimester of pregnancy, and then fade away temporarily to insignificance as pregnancies reach full term. The disappearance of social distinctions in rates of fetal loss coincides with the beginning of viability, suggesting that high-risk fetuses are disappearing from the fetal population and becoming extremely premature live births with high risks of infant death instead, distorting (under-stating) loss patterns for the fetal population remaining in utero. As full term approaches, the typical live-born infant gradually shifts from a high-risk pregnancy to a more normal profile, the risk-selective effect of live birth fades, and fetal mortality rates rise again producing a J-shaped pattern across gestational ages in the second and third trimesters overall.

Risk of spontaneous pregnancy loss also persists across repeated pregnancies for women, indicating that underlying individual characteristics play an important role linking successive reproductive outcomes. Women who have successfully given birth to a living infant have lower risks of fetal loss in subsequent pregnancies, and this selection effect appears to grow stronger with repeated demonstration of success represented by additional live births. By the same token, women who experience a spontaneous loss are more likely to lose a subsequent pregnancy, and this likelihood also appears to cumulate as repeated events sharpen this selection effect.

Induced abortion also comprises an important element of sexual and reproductive behavior, particularly in more developed societies, but also to a much less-well-understood extent in traditional societies both past and present. In some regions of the world, notably the former state socialist countries in eastern Europe and the European portions of the former Soviet Union, an actual majority of all recognized pregnancies in some years ended in induced abortions rather than live births. This phenomenon developed during the second half of the twentieth century, as governments encouraged early marriage and childbearing but failed to create conditions facilitating sustained family growth. Underdevelopment of effective alternative contraceptive methods in these countries combined with an early legalization of induced abortion as an element of women’s reproductive rights to produce a reliance on repeated induced abortion as the standard method of fertility control. For women utilizing abortions as a standard tool for fertility control after desired family size was achieved, the age profile of induced abortions shifts to considerably later ages in these countries than in most western developed countries where induced abortion more often concentrates among the youngest women.

In the United States and other western developed societies where induced abortion is legal, induced abortions account for a substantial minority of all pregnancy outcomes. While both live births and induced abortions concentrate heavily in the ages between 20 and 30 for women in these societies, the incidence of induced abortions relative to the number of births is highest among teenage women in the United States, with about one-third of all recognized teen pregnancies ending in induced abortions in the United States in 2000 while for women over age 30, only about one-fifth of all pregnancies ended in induced abortions. On the other hand, in Japan the age profile of abortion relative to births more closely resembled the eastern European case, with the highest proportion of pregnancies ending in abortion observed for women over age 30. The overall level of induced abortion for the United States is higher than observed in most other western industrial nations, rivaled only by Sweden or Australia. Research suggests that abortion rates in different countries are linked to differences in sex education and contraceptive knowledge and use among countries, as discussed in the next chapter on Family Planning.

In developing societies, induced abortion generally is less accepted by the general population. Health facilities capable of performing safe, legal abortions are less available to women. In a substantial number of countries, induced abortion is illegal or restricted. The consequence of such social and legal restrictions for pregnancy outcomes is that a smaller share (usually only a few percent) of pregnancies end in induced abortion. However, a significant share of the induced abortions that do occur in these settings are clandestine abortions, with very serious health consequences for women as noted in following sections on reproductive impairment and mortality.

2.2. Sexual Behavior and Reproductive Impairment

Reproductive health includes the ability of healthy adults to conceive and bear children as a result of their sexual activity. However, sexual and reproductive behavior can itself introduce impairments to this ability in at least two ways. First, sexual activity can lead to sexually transmitted infections that impair subsequent reproductive ability. Second, even successful pregnancies can involve subsequent medical complications that produce secondary sterility. In both cases, the sexual activity itself leads to reproductive impairment.

2.2.1. Reproductive Consequences of Sexually Transmitted Infections

Several common sexually contracted bacterial infections can cause partial or total sterility in women by scarring that obstructs the fallopian tubes, preventing passage of ova or fertilization. Chlamydia (infection by bacterial Chlamydia trachomatis) if untreated can produce the uterine infection known as pelvic inflammatory disease (PID), which can result in scarring that produces chronic pain, ectopic pregnancy, and other dangerous complications of pregnancy. Women infected with chlamydia also are up to five times more likely to become infected with HIV. Men contracting the infection can develop epididymitis, an infection of the testicles that can cause sterility. Chlamydia can cause spontaneous abortion, premature rupture of amniotic membranes and premature birth, blindness as a result of conjunctivitis, or pneumonia. Gonorrhea (infection by bacterial Neisseria gonorrheae) is one of the most common sexually transmitted infections in the world, with millions of cases contracted worldwide each year. Resulting inflammatory disease and associated scarring, as for other STIs, increase the risk of ectopic pregnancies and infertility in women, and can produce excretory azoospermia in men. Fortunately, nearly all these bacterial infections can be treated with antibiotics; unfortunately, in many parts of the world lack of such treatment leads to adverse reproductive health consequences including those above for hundreds of thousands of cases.

2.2.2. Secondary Sterility

Childbirth or abortion that takes place even under full medical supervision can result in secondary sterility (inability to become pregnant and bear subsequent children) in rare circumstances. However, this risk of secondary sterility is much higher for births and/or abortions performed without adequate medical facilities or supervision, including in particular the clandestine abortions that occur in many parts of the developing world where safe, legal abortion is often problematic. Although anxiety about fertility effects of female circumcision also has been recorded among respondents to health surveys in Africa, further research into the health effects of these controversial practices found that female circumcision was related to risks of hemorrhage, pain and even death for the women themselves, but that circumcised women showed no statistically significant differences in reproductive ability from other women. Among men, use of steroids and other medications can reduce sperm counts and result in impairment of reproductive ability. More generally, biomedical research has uncovered a steady and as-yet poorly understood decline in recent years of sperm density, widely distributed among men throughout most developed countries including the United States and western Europe as well as developed countries in other parts of the world. This decline may be related to presence of synthetic hormones and other chemicals in food and in other environmental sites, but no conclusive findings have yet emerged in this puzzling development for reproductive health.

2.2.3. Elective Sterilization

However, not all secondary sterility produced after termination of a pregnancy by live birth, spontaneous loss or induced abortion can be classified as an adverse reproductive health outcome. Increasingly, women in more and more countries are turning to elective tubal ligation or even hysterectomy as a supplementary procedure following a pregnancy termination (or as a separate surgical procedure apart from any pregnancy) to produce voluntary sterilization. This decision, typically taken by women who have attained their desired family size and who wish to end the risk of conception for the remainder of their premenopausal years of sexually active life, is routinely recorded as one fertility control strategy among others (including contraception, induced abortion, sexual abstinence and the like) in reproductive health surveys around the world, yielding an excellent overall statistical picture of this increasingly common practice. Less commonly but also important for patterns of reproductive health and behavior, men can elect to have the vas deferens tubes transmitting spermatozoa into the seminal fluid severed. Vasectomies, surgically much simpler and safer than the equivalent procedures of female sterilization, none the less remain less common in almost all societies and population groups due to psychological differences in attitudes and beliefs between men and women. For example, in the United States, nearly three times as many women as men have been surgically sterilized (18 percent versus 7 percent as of 2004), and the gender gap is much wider among ethnic minorities (25 percent of black women but only one percent of black men). Nearly all men obtaining vasectomies are married, but over one-third of women obtaining tubal ligations or hysterectomies are not married. For men and even more strongly for women, probability of electing sterilization in midlife to terminate the possibility of reproduction correlates very strongly and positively with education and socioeconomic status, reinforcing the conclusion based on gender differences that election of this procedure depends at least as much on psychological aspects of sexual identity as on tangible economic or other material considerations. In other developed countries the prevalence of sterilization varies. Less than ten percent of women and less than one percent of men in France have elected surgical sterilization. The highest level of male sterilization occurs in the United Kingdom, where 18 percent of men in couples of reproductive ages have had vasectomies. The UK and the Netherlands are the only countries in the world where the proportion of men sterilized exceeds the equivalent proportion for women among couples in the reproductive ages. The highest level of female sterilization among women of reproductive age occurs in China, with nearly one-third of all women relying on this method to regulate fertility. Across developing countries as a group, recent estimates place the share of women who have been sterilized at between 15 and 20 percent, quite comparable to levels in the United States, but sterilization among men has actually declined in recent years as earlier enthusiasm for this practice in Asia and developing countries in other regions wanes among younger generations. Female as well as male sterilization remains almost unknown in Africa.

2.3. Sexual Behavior, Reproductive Health and Adult Mortality

The most serious reproductive health consequence that may ensue from sexual behavior and resulting pregnancy and childbirth is death. While fetal and infant deaths were considered above, this section examines the risk of death for sexually active adults that may result directly from sexual activity itself in the form of lethal sexually transmitted disease, and that may follow from pregnancy as a result of sexual activity in the form of maternal mortality.

2.3.1. Sexual Behavior and Disease-Related Mortality

By far the most dramatic effect that sexual behavior can have on health concerns potentially lethal sexually-transmitted infections (STIs) such as human immuno-deficiency virus (HIV) and its sequelae including acquired immuno-deficiency syndrome (AIDS). Other sexually-transmitted diseases such as syphilis also can kill infected patients, but HIV and AIDS have become one of the most urgent health concerns in many parts of the world. HIV/AIDS as a lethal disease syndrome first came to the attention of the scientific and medical community in developed nations, where it often appeared at first among young male homosexuals and intravenous drug users.

The human immuno-deficiency virus does not produce disease and death as a result of its own existence in the body. Rather, it suppresses the ability of the human immune system to combat other diseases, opening the way for a range of rare cancers, tuberculosis, pneumonia, and other diseases that would not ordinarily be fatal in the presence of an active functioning immune system. After an indeterminate latency period (ranging from weeks to years) the virus reduces CD4 T-cells below critical levels, and opportunistic infections are able to invade the body and produce the diseases that eventually kill the patient. This terminal process is the actual acquired immuno-deficiency syndrome (AIDS), for which therapies but no cure exist in the early twenty-first century.

The virus is known to be spread by direct contact/sharing of specific body fluids, particularly blood, semen and other genital secretions, but also breast milk. Shared needle use accounted for spread of the disease among intravenous drug users. Research has shown that risk of transmitting the infection is far higher for anal than for vaginal intercourse. Although early research suggested that oral sex did not transmit the virus, this finding has been modified to a low risk of transmission by recent research. A wide range of health and public safety workers have adopted prophylactic practices including use of rubber gloves, masks and other protection when coming in contact with bodily fluids of patients and the public in the course of their duties. Sexual contact remains the most prevalent means of transmission of the infection. Although the placental barrier does provide protection for the fetus of an infected mother, in about one-fourth of vaginal deliveries involving HIV-positive women an infant is also born HIV-positive due to contact with the virus in the birth canal. Caesarian section procedures in appropriately sterile conditions can reduce the risk of transmission to about one case in a hundred. Other kinds of contact involving exposure to blood (medical procedures, interpersonal violence, accidents and the like) also continue to receive attention and preventive efforts.

Because HIV/AIDS appeared first in marginalized subcultural settings (among homosexuals and drug users) other social groups have been tempted to ignore or deny the prospect of risk to themselves. Wherever such inattention and denial have taken root, the insidious character of this syndrome has proved them wrong. Within the United States, ethnic subpopulations including Hispanics, African-Americans, Native Americans and others initially felt safe in ignoring a “gay white” disease. As a result, HIV infection rates and AIDS deaths now are many times higher among black Americans than among white Americans, for both men and women. Women at first erroneously regarded the syndrome as a purely male health problem, but quickly discovered that their own male partners sometimes were in contact with the subcultural settings where the disease first made its appearance, and ordinary heterosexual intercourse has become a major vector of transmission for the disease in all countries.

At the scale of entire countries much the same problems of inattention and denial have had similar health outcomes. Although the syndrome first attracted attention in developed nations, the less-developed countries of the world have become the macro-level counterparts of ethnic subpopulations within a developed country like the United States, today exhibiting the highest prevalence rates for HIV infection, higher case fatality rates due to less resources devoted to medical care and treatment, and greater prominence for heterosexual transmission of the virus. HIV/AIDS has spread most rapidly and extensively in central and eastern African nations, and more recently has made alarming inroads in the midst of the anomic social environments found in a number of former state socialist countries in eastern Europe and the former Soviet Union. Southeast Asia also has been hit hard by the epidemic, with the sex trade heavily implicated in the transmission process. Many countries, including China, are only beginning to come to grips with the necessity of admitting the possibility of a problem with this threat to health originating, to an important extent, in sexual behavior.

Early public health efforts to check the spread of HIV/AIDS employed widely-diffused public information campaigns to educate the general public about transmission mechanisms, behavioral risk factors, and prevention. The inefficiencies of aiming most of these efforts at the majority of the population with only minimal exposure to risk, however, gradually prompted authorities and experts to modify these efforts. More intensive interventions and informational campaigns aimed specifically at “hot spots” within the population (specific neighborhoods/cities where specific high-risk groups reside and specific channels of communication through which these groups interact) proved more successful, and over the past two decades most developed nations have shown steady progress in not only limiting but reducing the prevalence of existing cases and incidence of new cases. The key to these successes has rested on the willingness of leaders in the public and private sectors to tackle the subject directly and openly in the media, in the workplace, and in other public forums; on the commitment of health authorities to devote resources of money and manpower for research and for support of intervention and public information campaigns; and on widespread public acceptance of specific health practices including use of barrier methods by sexual partners, increased rates of male circumcision, and treatment of other sexually transmitted infections that often act as cofactors in the spread of the HIV virus..

Other sexually transmitted infections also can pose lethal risks in human populations, including syphilis, a bacterial infection easily treated with antibiotics, but which has a long latency period and very diverse effects on the circulatory system, brain, bones, eyes, and other systems, in some cases leading to dementia and/or death. The lethality of syphilis has evolved to lower levels in affected populations over recent centuries, being fatal much more often when first introduced into European populations in the 1400s. In addition to killing infected persons, syphilis is associated with elevated risks of fetal deaths for pregnant women infected with the disease. Certain strains of human papilloma virus (HPV) have been linked to cervical dysplasia, a precursor of cervical cancer, but a vaccine effective against several of the HPV strains implicated in this disease process has been developed and is being administered in the United States and other developed societies.

2.3.2. Maternal Mortality

The World Health Organization has defined a maternal death as “the death of a woman while pregnant or within 42 days of termination of pregnancy, irrespective of the duration and the site of pregnancy, from any cause related to or aggravated by pregnancy or its management, but not from accidental or incidental causes.” National definitions may further refine the definition of pregnancy-related causes as distinguished from other causes of death. The pregnancy-related mortality ratio (PRMR) in the United States recorded about 13 pregnancy-related deaths per 100,000 live births at the start of the twenty-first century, but rates in the poorest developing countries can be many times higher. The risk of a woman dying as a result of pregnancy or childbirth during her lifetime is about one in six in the poorest parts of the world compared with about one in 30,000 in Northern Europe.

In recent years in the United States, the major causes of pregnancy-related death were embolism, hemorrhage, complications of medical conditions, and hypertensive disorders of pregnancy. Despite a relatively low level of maternal mortality in the United States, the pregnancy-related mortality ratio has remained almost unchanged for more than a decade, and at least half of pregnancy-related deaths may be preventable through changes in patient, provider, or system factors; maternal mortality occurs disproportionately often among certain racial and ethnic groups. Black women are more than twice as likely as Hispanic women to die during pregnancies, and Hispanic women are almost twice as likely to die as white women (Geller et al 2006), at least in part as a result of socioeconomic differences in the social contexts experienced by different ethnic groups.

In the poorest countries, inferior health care delivery systems and continuing high fertility contribute to the elevated risk of maternal mortality. Postpartum hemorrhage is the most common cause of maternal death across the world, accounting for at least one-fourth of all maternal deaths. The Safe Motherhood Initiative, begun in 1984, is a global effort to reduce deaths and illnesses among women and infants, but progress has been very slow. Techniques used to reduce hemorrhage deaths in developed countries cannot easily be introduced in the poorest regions of the developing world, due to lack of training of birth attendants to perform diagnoses using appropriate blood measurement tools, to lack of refrigeration for effective uterotonics and other medicines, and to lack of effective rapid methods of transportation to tertiary care settings. Hemorrhage was the leading cause of maternal death in Africa and in Asia, but hypertensive disorders rivaled or even sometimes exceeded hemorrhage as a cause of maternal death in Latin America and the Caribbean. Abortion complications sometimes can lead to a woman’s death, most frequently relative to other causes in Latin America and the Caribbean where nearly one-third of all maternal deaths may be abortion-related in some countries. Due to the very high rates of induced abortion relative to births in eastern Europe and the former Soviet Union, abortion-related complications also figure in a high proportionate share of maternal deaths in that region. Interventions focused on rural populations and poor people offer the greatest promise of progress in the near future in these countries.

2.4. Health Impact of Violent Sexual Behavior

While most sexual interaction involves consenting partners, the strong biological drives underlying sex behavior combine with problematic social contexts (deviant socialization, highly asymmetric power relationships, commercialization of sex, social disorganization and conflict) to produce an undercurrent of violent sexual behavior that can have devastating physical and mental health consequences for those caught in these situations.

2.4.1. Social Crisis and Organized Sexual Violence

Sexual violence directed against individual victims (child sexual abuse, rape, forced sex within marriage, and the like) usually is studied in contexts where partners, family members or other perpetrators are acting on their own, in ways usually regarded as deviant or even illegal by the surrounding community. However, it is important to recognize that in exceptional circumstances sexual violence actually may become a form of organized, sanctioned social behavior. In civil wars, ethnic or religious conflicts, conflicts over natural resources or territory, and the like, rape and other violent sexual assault can become deliberate weapons of war. Extensive media coverage of recent conflicts in the Balkans, in Africa, in the Middle East, in south Asia, and in other parts of the world has created new awareness of what in fact has been a pattern throughout history in most parts of the world. Women, children and other defenseless civilians caught up in organized conflict easily become victims of armed combatants, and sexual violence becomes a part of this victimization. Refugees fleeing from conflict also can be victimized by border guards, by local populations where they seek refuge, and even by one another. In addition to injuries, possible death, and long-term reproductive impairments resulting from sexual trauma, such organized sexual violence can produce widespread incidence of unwanted pregnancies, with related risks of suicide and “honor killings” of raped and pregnant women.

2.4.2. Violence in Early Life and Reproductive Health

The tangled relation between violent behavior and reproductive health problems is not limited only to sexual violence (forcible sexual intercourse and other directly sexual violent acts). Women who experience violence (including sexual violence) early in life have earlier ages at first intercourse, possible psychopathological propensities attracting them to violent partners, higher probabilities of multiple sexual partners, consequent greater risks of acquiring sexually transmitted infections and also of conceiving unwanted pregnancies, more early pregnancies with elevated risks of adverse birth outcomes, shorter birth intervals with associated adverse birth outcomes, and a greater likelihood of engaging in abusive behavior of children themselves. These patterns are related both to the disadvantaged circumstances in which women experiencing early-life violence are more likely to grow up (a selection effect) and to the psychological consequences of the violence itself for their emotional and physical well-being. Women who experience child sexual abuse also are less likely to enter and to remain in stable marriages and other intimate unions, reducing their chances of having children and also reducing the resources available to them in the event of pregnancy and childbirth. This pattern represents yet another channel by which sexual violence can exert negative effects on subsequent reproductive health not only for victims but for subsequent generations. Men who experience child sexual abuse are more likely to engage in risky behaviors including experimentation with drugs and unprotected sex with multiple partners. They are more likely to use violent behavior in their own relationships later in life, and like abused girls, are less likely to remain in stable adult unions.

2.4.3. Violence in Adulthood and Reproductive Health

Men have been found to commit acts of sexual violence more frequently when they are involved in alcohol use and when they have multiple sexual partners. Women can experience violence as a result of resisting partner requests for sexual contacts, in disputes over use of contraceptive methods, and also for clandestine use of contraceptives. In many cultures, men with violent tendencies who find themselves in social settings that permit violent acts against their partners (social/geographic isolation, extreme inequality in power/status relations, complicity by neighbors and kin) can actually obtain rewards such as more frequent sexual intercourse as a result of their violent behavior. Some women experience violence as a partner or other significant other’s reaction to their pregnancies; non-marital pregnancies in some traditional cultures (for example, in the Middle East) can provoke violence against women by male relatives, including physical injury and even death. Partners also may react violently to a pregnancy; in a village study in India, one-sixth of all deaths during pregnancy involved partner violence. Forced sex leads to unwanted pregnancy with attendant adverse health outcomes for women and also for their children, both in the proximate birth environment and throughout their later lives. Physical violence during pregnancy can produce fetal loss or premature delivery with attendant low birth weight.

Studies of partner violence and other sexual violence in adulthood often find strong correlations between the prevalence of such incidents and higher infant mortality, and other adverse reproductive health outcomes. However, few of these studies have adequately addressed the distinction between direct causation of reproductive health problems as a result of violence (for example, spontaneous loss as a result of abuse of a pregnant woman) and simple correlation of these health issues by virtue of social, economic, and other characteristics that strongly predict both violent behavior and poorer reproductive health.

Glossary

famine amenorrhea - temporary cessation of ovulatory/menstrual cycle as a result of sudden and pronounced deprivation of food.

menarche - onset of the ovulatory/menstrual cycle.

menopause - final, permanent cessation of the ovulatory/menstrual cycle upon exhaustion of ovaries.

preecclampsia - potentially serious condition developing in the third trimester of a pregnancy and marked by high blood pressure and fluid retention.

post-partum taboo - cultural prohibition of sexual intercourse following birth, usually coinciding with lactation and nursing but sometimes extended for much longer periods of time.

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