The Pregnant Family-- Unit II-A Conception and Biophysical ...



Mennonite College of Nursing

at

Illinois State University

Parent Child Nursing 323

Lecture Guide

The Pregnant Family-- Unit II-A Conception and Biophysical Changes

Unit II-B Psychosocial Changes

I. PREGNANCY

A. Conception

1. Necessary functional components

a. uterus

b. fallopian tubes

c. ovaries (eggs)

d. hormones

e. sperm

2. Fertilization & implantation

a. process over time

Ovum

(

Fertilized Ovum

(

Zygote (Pronuclei Stage)

(

1st Mitotic Division

(

2-Cell Zygote (1 1/2 days later)

(

16-Cell Morula (3 days)

(

58-Cell Blastocyst (4 days)

(

107-Cell Unilaminar Blastocyst (4 1/2 days)

(

Several Days Pass Until Bilaminar Blastocyst Implants (6 days)

b. double layer development

1) blastocyst - inner layer - solid

2) trophoblast - outer layer - foraging layer (feeding layer)

c. implantation

d. trophoblast to chorion

B. Embryology & Fetal Development

1. Development of fetus in lunar months (see foldout between pp, 636-637 in Olds.)

(Review Table 11-2 in text, "Summary of Organ System Development ", pp. 239-240.)

a. 1st LM-- heart developing--beginning to beat; well-arked midbraing flexure

b. 2nd LM--1st indication of ossification, definitive muscles well represented

c. 3rd LM-- nails appearing, skin pink,kidney able to secrete urine, sex organs recognizable

d. 4th LM--head still dominant, meconium in bowel,

e. 5th LM--vernix caseosa & lanugo appearing, nostrils reopening, brain grossly formed; nose and ears ossifying

f. 6th LM--body lean but fairly well proportioned;nose & ears ossifying,ability to hear, eyelids still fused or beginning to open

g. 7th LM--weak, fleeting movements; minimum tone; lecithin forming on alveolar surfaces; eyelids reopening

h. 8th LM--L/S ratio 2:1, subq fat appearing, more rounded appearance, sense of taste present, testes descending to scrotum

i. 9th LM--L/S ratio > 2:1, definite sleep-wake cycles, skin pink becoming rounded

j. 10th LM--pulmonary branching only 23 completed;strong suck reflex

C. Placental Development

1. Formation by 3rd lunar month

a. decidua basalis (mother's portion)

b. chorionic villi (fetal portion)

2. Placental facts

a. size of 8-inch dinner plate

b. consists of 15-20 cotyledons, chorionic villi branch out from it

c. structure is complete at the end of 12th week gestation

d. grows till 20th week gestation, covers ½ of uterine surface.

3. Functions

a. transfer nutrients

b. diffuses oxygen and carbon dioxide functioning as fetal lungs

c. produces 4 hormones essential to maintain pregnancy: hCG, hCS/hPL, progesterone,

& estrogen

d. facilitates transfer of metabolic wastes from the fetus to the maternal circulation

e. transfers heat from mother to fetus

D. Signs and Symptoms of Pregnancy—this is important to know

1. Presumptive signs of pregnancy (subjective)

a. menstrual suppression (amenorrhea, menstruation may occur after conception)

b. nausea, vomiting, and "morning sickness" (due to increased HCG levels)

c. frequency of micturition (uterus stretches base of bladder)

d. tenderness and fullness of the breasts, breast pigmentation, and discharge (due to increased progesterone, estrogen)

e. "quickening" (usually 18-20 wks. may be 16 wks. in multigravida)

f. fatigue

2. Probable signs (objective)

a. dark blue discoloration of the vaginal mucous membrane known as

CHADWICK'S SIGN

b. pigmentation of the skin and abdominal striae (may also occur in breasts, buttocks, and thighs)

c. changes in the size, shape, and consistency of the uterus - HEGAR'S SIGN (lower part of the body of uterus much softer than cervix)

d. fetal outline, distinguished by abdominal palpation and detection of a fetal part vaginally by ballottement (sudden tap on presenting part makes it rise in amniotic fluid)

e. changes in the cervix (GOODELL'S SIGN - cervix softens due to increased vascularity edema)

f. BRAXTON HICKS contractions (painless, cause of false labor)

g. positive pregnancy test (increased Hcg levels, blood/serum 8-9 days after ovulation and fertilization and urine test within 2 wks of gestation)

3. Positive signs (diagnostic)

a. fetal heart sounds (audible with Doppler 8-10 weeks gestation, or ultrasound)

b. fetal movements felt by examiner

c. x-ray- outline of fetal skeleton

d. ultrasonic demonstration of the presence of a conceptus (6-8 wks. yields most information

e. fetal movements visible

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