Hormonal Physiology of Childbearing: Evidence and ...

Hormonal Physiology of Childbearing: Evidence and Implications for

Women, Babies, and Maternity Care

Sarah J. Buckley January 2015

Childbirth Connection

A Program of the National Partnership for Women & Families

About the National Partnership for Women & Families At the National Partnership for Women & Families, we believe that actions speak louder than words, and for four decades we have fought for every major policy advance that has helped women and families.

Today, we promote reproductive and maternal-newborn health and rights, access to quality, affordable health care, fairness in the workplace, and policies that help women and men meet the dual demands of work and family. Our goal is to create a society that is free, fair and just, where nobody has to experience discrimination, all workplaces are family friendly and no family is without quality, affordable health care and real economic security.

Founded in 1971 as the Women's Legal Defense Fund, the National Partnership for Women & Families is a nonprofit, nonpartisan 501(c)3 organization located in Washington, D.C.

About Childbirth Connection Programs Founded in 1918 as Maternity Center Association, Childbirth Connection became a core program of the National Partnership for Women & Families in 2014. Throughout its history, Childbirth Connection pioneered strategies to promote safe, effective evidence-based maternity care, improve maternity care policy and quality, and help women navigate the complex health care system and make informed decisions about their care. Childbirth Connection Programs serve as a voice for the needs and interests of childbearing women and families, and work to improve the quality and value of maternity care through consumer engagement and health system transformation.

? 2015 National Partnership for Women & Families. All rights reserved.

This publication may be redistributed electronically or digitally for noncommercial purposes only so long as it remains wholly intact, including this copyright notice and disclaimer. Address all other permission requests, except for brief quotations with credit to the source, to Childbirth Connection Programs, National Partnership for Women & Families.

Disclaimer: The information provided in this report is not intended as a substitute for the professional guidance of qualified maternity care providers.

Suggested citation: Buckley, Sarah J. Hormonal Physiology of Childbearing: Evidence and Implications for Women, Babies, and Maternity Care. Washington, D.C.: Childbirth Connection Programs, National Partnership for Women & Families, January 2015.

Available with related documents at: HormonalPhysiology

1875 Connecticut Avenue NW, Suite 650, Washington, D.C. 20009

phone: 202-986-2600 ? fax: 202-986-2539 ? e-mail: info@

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Abstract

Hormonal Physiology of Childbearing: Evidence and Implications for Women, Babies, and Maternity Care

This report synthesizes evidence about innate hormonally-mediated physiologic processes in women and fetuses/newborns during childbearing, and possible impacts of common maternity care practices and interventions on these processes, focusing on four hormone systems that are consequential for childbearing. Core hormonal physiology principles reveal profound interconnections between mothers and babies, among hormone systems, and from pregnancy through to the postpartum and newborn periods. Overall, consistent and coherent evidence from physiologic understandings and human and animal studies finds that the innate hormonal physiology of childbearing has significant benefits for mothers and babies. Such hormonally-mediated benefits may extend into the future through optimization of breastfeeding and maternal-infant attachment. A growing body of research finds that common maternity care interventions may disturb hormonal processes, reduce their benefits, and create new challenges. Developmental and epigenetic effects are biologically plausible but poorly studied. The perspective of hormonal physiology adds new considerations for benefit-harm assessments in maternity care, and suggests new research priorities, including consistently measuring crucial hormonally-mediated outcomes that are frequently overlooked. Current understanding suggests that safely avoiding unneeded maternity care interventions would be wise, as supported by the Precautionary Principle. Promoting, supporting, and protecting physiologic childbearing, as far as safely possible in each situation, is a low-technology health and wellness approach to the care of childbearing women and their fetuses/newborns that is applicable in almost all maternity care settings.

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Contents

Abstract .......................................................................................................................................................... i Figures and Tables ...................................................................................................................................... iii Message from Debra L. Ness ...................................................................................................................... iv Foreword ....................................................................................................................................................... v Preface ........................................................................................................................................................ vii Acknowledgments ...................................................................................................................................... ix Executive Summary ...................................................................................................................................... x

1 Introduction: Overarching Themes and Scope ............................................................................. 1 1.1 Human Childbearing: Evolution and Safety .......... 2 1.2 Contemporary Childbirth Practices .......... 2 1.3 Current Understandings of the Hormonal Physiology of Childbearing .......... 4 1.4 Alignment with Other Frameworks .......... 7 1.5 Scope of This Report .......... 10 1.6 Introduction: Summary .......... 11

2 Physiologic Onset of Labor and Scheduled Birth ......................................................................... 14 2.1 Physiologic Onset of Labor at Term .......... 15 2.2 Possible Impacts of Scheduled Birth .......... 20 2.3 Physiologic Onset of Labor and Scheduled Birth: Summary .......... 24

3 Oxytocin ............................................................................................................................................ 26 3.1 Oxytocin: Normal Physiology .......... 27 3.2 Common Maternity Care Practices That May Impact Oxytocin Physiology .......... 54 3.3 Oxytocin Physiology: Summary .......... 90

4 Beta-Endorphins ............................................................................................................................. 93 4.1 Beta-Endorphins: Normal Physiology .......... 94 4.2 Common Maternity Care Practices That May Impact Beta-Endorphins Physiology .......... 102 4.3 Beta-Endorphins: Summary .......... 109

5 Epinephrine-Norepinephrine and Related Stress Hormones .................................................. 111 5.1 Epinephrine-Norepinephrine and Related Stress Hormones: Normal Physiology .......... 112 5.2Common Maternity Care Practices That May Impact Epinephrine-Norepinephrine

and Related Stress Hormones .......... 125 5.3 Epinephrine-Norepinephrine and Related Stress Hormones: Summary .......... 138

6 Prolactin ........................................................................................................................................ 140 6.1 Prolactin: Normal Physiology .......... 141 6.2 Common Maternity Care Practices That May Impact Prolactin Physiology .......... 149 6.3 Prolactin: Summary .......... 154

7 Conclusions and Recommendations ........................................................................................... 156 7.1 Conclusions .......... 157 7.2 Recommendations to Promote, Support, and Protect Physiologic Childbearing .......... 163 7.3 Conclusions and Recommendations: Summary .......... 169

Appendix: Resources for Learning More and Improving Practice ...................................................... 171 References ................................................................................................................................................ 175 Abbreviations ........................................................................................................................................... 224 Photo Credits ............................................................................................................................................ 225

CHILDBIRTH CONNECTION | HORMONAL PHYSIOLOGY OF CHILDBEARING | CONTENTS

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Figures and Tables

Figures

Figure 1: Women's oxytocin levels in late pregnancy, in early labor, at birth, and after birth.............. 36 Figure 2: Maternal oxytocin levels, with and without epidural analgesia......................................... 76 Figure 3: Women's beta-endorphins levels non-pregnant, in labor, and after birth........................... 99 Figure 4: Maternal beta-endorphins levels, with and without epidural analgesia............................ 106 Figure 5: Maternal epinephrine and norepinephrine levels in labor, at birth, and after birth .......... 119 Figure 6: Maternal epinephrine and norepinephrine levels, with and without epidural analgesia ..... 132 Figure 7: Maternal prolactin levels in labor, at birth, and after birth............................................. 145 Figure 8: Maternal prolactin levels, with and without epidural analgesia....................................... 152

Tables

Table 1: Established and biologically plausible adverse impacts of labor induction and prelabor cesarean .................................................................................................................... 22

Table 2: Established and biologically plausible impacts of physiologic versus synthetic oxytocin in labor and birth ......................................................................................................... 57

Table 3: Established and biologically plausible oxytocin processes and impacts, by type of cesarean.... 82 Table 4: Established and biologically plausible impacts of common maternity care interventions on

four hormone systems ............................................................................................... 158

CHILDBIRTH CONNECTION | HORMONAL PHYSIOLOGY OF CHILDBEARING | FIGURES AND TABLES

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Message from Debra L. Ness

It is with great pride that we release Hormonal Physiology of Childbearing: Evidence and Implications for Women, Babies, and Maternity Care. We issue this report at a moment when there is growing recognition that patterns of maternity care in the United States are contributing to unnecessarily high rates of maternal and newborn morbidity and mortality and excess costs. The past year has brought important progress, including position statements from clinical professional societies that call for better alignment of practice with the best evidence and with the needs and interests of women and families. With this report, Childbirth Connection programs at the National Partnership for Women & Families adds strength and urgency to the case to improve the quality and value of maternity care in the United States.

Founded in 1918 as the Maternity Center Association, Childbirth Connection has worked for nearly a century to improve the quality of maternity care on behalf of women and families. A year ago, Childbirth Connection joined forces with and became a core program of the National Partnership, which has a powerful, long-term commitment to quality, affordable health care. Together, we have become a stronger and even more effective force advocating for the needs and interests of childbearing women and families and for maternity care system reform.

For Childbirth Connection programs at the National Partnership, the release of this report is the first step in our work to ensure that its key messages reach diverse audiences and that its recommendations are promoted and adopted by the policy, practice, education, consumer engagement and research communities. Much of this dissemination is being done in partnership with key organizations, agencies, and leaders. We invite all who are committed to the highest standard for maternity care to join us in this work.

I am enormously grateful to all who contributed to this report. Dr. Sarah Buckley's synthesis of the vast literature compels us to move forward to transform maternity services. The five clinical leaders from the most relevant disciplines who wrote the Foreword are invaluable allies as we release the report and take the next steps. Carol Sakala, director of Childbirth Connection programs, and Maureen Corry, senior advisor for Childbirth Connection programs, have shepherded this project every step of the way and made great strides in integrating Childbirth Connection within the National Partnership. Together, we thank the many leaders who provided wise counsel through interviews and who will help us bring the report to essential audiences. And without question, this project would not have been possible without generous funding and support from the Transforming Birth Fund, Lamaze International, and DONA International.

We look forward to working with both established and new allies to reach the day when all women in this country can count on safe and effective maternity services that foster optimal maternal health and give babies the best start in life.

Debra L. Ness, President National Partnership for Women & Families

CHILDBIRTH CONNECTION | HORMONAL PHYSIOLOGY OF CHILDBEARING | MESSAGE FROM DEBRA L. NESS

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Foreword

This report, prepared by Dr. Sarah Buckley in collaboration with Childbirth Connection Programs at the National Partnership for Women & Families, will be retrospectively evaluated as one of the most revolutionary and influential publications on maternity and newborn care ever issued. What is remarkable is that it is not about a new technology or drug. Rather, it compiles scientific evidence that "less is more" and if we get it right in the beginning there are potentially profound impacts on learning, brain development, and well-being in the child.

As leaders from family medicine, midwifery, nursing, obstetrics, and pediatrics, we applaud the stellar compilation of scientific evidence on the hormonal physiology of childbearing. Buckley carefully weaves the hormonal lattice of oxytocin, beta-endorphins, epinephrine and norepinephrine and their related stress hormones, and prolactin to help the reader absorb the exquisite complexity of spontaneous labor, birth, maternal-infant attachment, and lactation. Physiologic preparation for birth is beautifully choreographed in pregnancy with critical hormonal and physical changes unfolding in the weeks, days, and (to date, only in animal studies) hours that lead to labor. The prelabor hormonal changes are neuroprotective in animal studies. The catecholamine surge in late labor is neuroprotective in humans. The critical message is to protect those processes for the health of the mother, the baby, and the future health of the child.

Our maternity care system works from a premise that "more technology is better." Buckley dispels this myth by exposing how the hormonal balances of childbearing, bonding with parents, and lactation may suffer from cascades of interventions. Evidence is becoming clear that the body recognizes medications and procedures intended to artificially simulate labor and birth processes as counterfeits. Tools such as induction and epidurals are used at the cost of disrupting delicate interconnections that are biologically designed to optimally prepare baby and mother for birth. Mothers and babies are well designed for birth; interfering with the process when mother and baby are healthy is not supported by evidence and may cause unintended harm. That harm is expressed in the short term through prolonged labors and unnecessary surgical births. Findings from animal models suggest short-, medium-, and long-term implications including, but not limited to, impaired lactation, diminished maternal attachment, effects on infant brain development and learning, and lifelong health. If overtreatment is defined as instances in which an individual may have fared as well or better with less or perhaps no intervention, then modern obstetric care has landed in a deep quagmire. Navigating out of that territory will be challenging.

The guidepost for the journey must steer us steadfastly down the path of "first, do no harm" in which we have been carefully schooled, but have not necessarily heeded. The "Precautionary Principle," which requires demonstration of safety before introducing interventions that may adversely affect labor, birth, and the newborn, must become the mantra in maternity care practice. Every setting providing maternity and newborn care must critically evaluate its common maternity care routines and practices against the evidence presented in this report. Policies at every level must change to afford women the opportunity to achieve a healthy physiologic birth.

Buckley provides us with an opportunity to connect with a growing broad audience of stakeholders, including providers, academicians, researchers, administrators, and consumers, about resetting the trajectories for health and well-being over the life course. Of these, the most crucial to reach are women and their families who want the very best for their child. We are aiming to achieve an era in which health care decisions are shared between the provider and client. Yet, most women and sadly, many providers do not know the information featured in this report.

CHILDBIRTH CONNECTION | HORMONAL PHYSIOLOGY OF CHILDBEARING | FOREWORD

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Systems can be changed. The National Institutes for Health and Care Excellence (NICE), which holds Department of Health responsibility for developing guidance and quality standards in England and Wales, released a groundbreaking 2014 Intrapartum Guideline just weeks before this publication. They recommended that at least 45 percent of low risk women should give birth outside of the hospital in birth centers or at home to avoid unnecessary interventions and harm. They have acted on the evidence within an integrated and responsive health care system. Our challenge is to consider how to best move forward with the findings from this report. Minimally, we would recommend the following:

1. This monograph needs to be shared with all physicians, midwives, and nurse providers of maternity and newborn care and administrative leadership of our maternity care units.

2. Basic and advanced curricula for physicians, nurses, and midwives should be interprofessional and founded on this evidence.

3. High-level opinion leaders and decision makers within health care systems and policy making bodies must understand how crucial it is to act on these findings to achieve our triple aim of a) improving the patient experience of care (including quality and satisfaction), b) improving the health of populations, and c) reducing the per capita cost of health care.

4. Strategies must be implemented to help women and their families understand how crucial it is to trust the capability of their body and the fetus in pregnancy and childbearing processes. However, this is not enough if maternity care settings do not provide the environments that support hormonal physiology.

5. Research to further our understanding of the evidence presented in this report is important. However, it should not preclude adoption of what is clearly understood ? that supporting physiologic childbearing processes is good for the mother and baby. What will be as important is to understand what helps maternity care practices and units successfully implement the findings from this report.

Holly Powell Kennedy, PhD, CNM, FACNM, FAAN Helen Varney Professor of Midwifery, Executive Deputy Dean, Yale University

Katherine Hartmann, MD, PhD, FACOG Associate Dean for Clinical and Translational Scientist Development, Professor of Obstetrics and Gynecology and Medicine, Vanderbilt University

Maxine Hayes, MD, PhD, MPH, FAAP Clinical Professor of Pediatrics, University of Washington Retired State Health Officer, Washington State Department of Health

Lawrence Leeman, MD, MPH Professor of Family Medicine and Obstetrics & Gynecology, University of New Mexico

Kathleen Rice Simpson, PhD, RNC, CNS-BC, FAAN Perinatal Clinical Nurse Specialist Editor in Chief, MCN: The American Journal of Maternal Child Nursing

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