Fetal Development and Tests for Fetal Wellbeing
Chapter 13
1. What is the difference between mitosis and meiosis?
 Mitosis: body cells replicate to yield 2 cells with the same genetic makeup as the
parent cell. Division facilitates growth and development or cell replacement.
 Meiosis: process by which germ cells divide and decrease their chromosomal
number by half, producing gametes (eggs and sperm).
2. When does an oocyte become a zygote?
 At fertilization, when the sperm is united with the mature ovum, a second polar
body and the zygote (the united sperm and egg) are produced.
3. How many sperm are usually in an ejaculation?
 200-500 million.
4. How long do sperm live in the female reproductive system? I didn’t know some could
reach the oocyte within five minutes!
 2-3 days on average.
5. Where does fertilization usually take place?  in the ampulla, or the outer third of the uterine tube.
6. What are the germ layers: ectoderm, mesoderm and endoderm and what do each of
these develop?  Ectoderm: upper layer of the embryonic disk that gives rise to the epidermis, the
anterior pituitary, cutaneous, and mammary glands, the nails and hair, the central
and peripheral nervous system, the lens of the eye, the tooth enamel, and the floor
of the amniotic cavity.
 Mesoderm: the middle layer that develops into the bones and teeth, the skeletal,
smooth, and cardiac muscles, the dermis and connective tissue, the cardiovascular
system and spleen, and the urogenital system.
 Endoderm: the lower layer that gives rise to the epithelium lining the respiratory
and digestive tracts, and the glandular cells of associated organs, including the
oropharynx, the liver and the pancreas, the urethra, the bladder, and the vagina.
The endoderm also forms the roof of the yolk sac.
7. What are the embryonic period and the fetal period?
 Embryonic period: day 15 until approximately 8 weeks (everything is begun
development) after conception. The embryo measures 3 cm from rump to crown.
 Fetal period: lasts from 9 weeks (when the fetus becomes recognizable as a
human being) until the pregnancy ends.
8. When is a baby most susceptible to the negative effects of teratogens? Also see brief
discussion on page 331, pg 317 critical times.  Embryonic period (days 15-60).
 Greatest effects on the organs and parts of the embryo during its periods of rapid
growth and differentiation.
 During the first 2 weeks, teratogens either have no effect or have effects so severe
that they cause miscarriages.
9. What are the two fetal membranes called? Which one is closest to the baby?
 Begin to form at time of implantation.
 Chorion: develops from the trophoblast and contains the chorionic villi on its
surface. The villi burrow into the deciduas basalis and increase in size and
complexity as the vascular processes develop into the placenta. It becomes the
covering of the fetal side of the placenta and contains the major umbilical blood
vessels.
 Amnion: the inner cell membrane develops from the interior cells of the
blastocyst. The cavity that develops between this inner cell mass and the outer
layer of cells (trophoblasts) is the amniotic cavity. The developing embryo draws
the amnion around itself forming the fluid filled sac. The amnion becomes the
covering of the umbilical cord and covers the chorion of the fetal surface of the
placenta.
 The amnion blends with the umbilical cord and is closer to the baby, while the
chorion blends with the placenta and is fused to the amnion.
10. Look at figure 13-6. If a mom got a severe infection between 5 and 6 weeks gestation,
what kind of defect might the baby have at birth? Also check out Table 13-1 p. 328-330.
 NTD, TA, ASD, VSD, cleft lip, lowest or malformed ears with hearing problems,
cataracts, glaucoma, micropthalmia.
11. What are oligohydramnios and hydramnios?
 oligo: <300ml, associated with fetal renal abnormalities.
 oligo early: baby renal problems
 oligo late:
 hyda: >2 L, associated with GI and other malformations.
12. What is the purpose of Wharton’s Jelly in the umbilical cord?
 Prevents compression of the blood vessels and ensures continued nourishment of
the embryo/fetus.
13. What is one of the early functions of the placenta?
 Endocrine gland that produces4 hormones necessary to maintain the pregnancy
and support the embryo and fetus.
 The functional part of the placenta is the syncytium
14. Refresh your memory on fetal circulation (Fig. 13-9).
 Pg 322
15. What is an L/S ratio? It has to do with the respiratory system.
 It is the measure of lecithin in relation to sphingomyelin and is used to determine
fetal lung maturity. Lecithin is the most critical alveolar surfactant required for
postnatal lung expansion.
16. Due to its immunological system, why is a preterm infant at greater risk for
infection?
 Only IgG crosses the placenta to provide passive acquired immunity to specific
bacterial toxins. The fetus produces IgM by the end of the first trimester in
response to organisms. IgA is not produced by the fetus, but provided in
colostrum giving passive immunity to those who breastfeed.
18. What are dizygotic twins and monozygotic twins?
 Dizygotic: 2 mature ova produced in one ovarian cycle, both of them can be
fertilized by separate sperm. There are 2 amnions, 2 chorions, and 2 placents.
 Monozygotic: identical, one fertilized ovum which then divides. They are the
same sex and have the same genotype. There are 2 embryos, 2 amnions, and
there can be 1 or 2 chorions and 1 or 2 placentas.
19. What are you if you are an XX or an XY?
 XX: girl
 XY: boy
Chapter 29: Are you okay in there? Check out ATI Chapter 7 too! Pg 767 fetal
assessment test table.
1. We know utero-placental insufficiency shows up as late decelerations in labor. What
other serious things does it cause (check out Box 29-2 also)?
 Fetal growth restriction, Intrapartum death, intrauterine death, Intrapartum fetal
distress, and various types of neonatal morbidity.
2. Take a look at Box 29-1 (p. 764) How many of these are amenable by primary
prevention? How can we as nurses, in roles "beyond the bed rails" contribute to
prevention?
 Smoking, nutrition, drugs, alcohol, caffeine, prenatal care are all preventable.
 Education programs.
3. In general what are ultrasounds used for (Table 29-2)?
 1st: confirm pregnancy, viability, gestational age, r/o ectopic, multiple gestations,
visualization during chorionic villus sampling, maternal abnormalities.
 2nd: confirm dates, viability, AFI, congenital anomalies, placenta placement,
visualization for amnio.
 3rd: confirm gestational age, viability, macrosomia, congenital anomalies, IUGR,
fetal position, placenta previa or abruptio placentae, visualization for amnio or
external version, BPP, AFI Doppler flow studies, placental maturity.
4. What’s the BPD?
 Biparietal diameter should be 8.7 cm at 36 weeks.
5. What are symmetric and asymmetric IUGR? Which one’s “better’?
 Asym: Head is bigger than body (head sparing) d/t later insults r/t disease
processes in mother HTN, renal disease, placenta deficiency, nutrition, or
cardiovascular disease.
 Sym: small everywhere d/t chronic long standing insult (smoking, nutrition,
infection, chromosomal abnormalities)
 I would pick asym because better than chronic.
6. What can fetal nuchal translucency be used for? What is an abnormal finding?  FNT is a prenatal screening that measures fluid in the nape of the fela neck
between 10-14 weeks to identify possible fetal abnormalitites.
 Abnormal fluid collection is > 2.5 mm, 3+ mm is highly indicative of genetic
disorders and or physical anomalies.
7. Using Doppler Blood Flow analysis, which is not good: an elevation of S/D ratios or a
decrease in S/D ratios?
 Systolic and diastolic ratios via the umbilical and uterine arteries.
 Normal ratios decrease as pregnancy advances sue to a progressive decline in
resistance in the arteries.
 Increase is not good because it means more resistance in blood flow through
umbilical artery.

Most fetuses will have an S/D ratio of 3 or less by 30 weeks. Persistent elevation
of ratis after 30 weeks is associated with IUGR, usually resulting from IUP.
8.What’s an AFI and what is normal?  Amniotic fluid index based on pockets. Abnormalities usually associated with
fetal disorders.
 <5 not enough (oligo), 5-19 normal, >19 too much (hydram).
 Placenta ages and decreases nutrients and decreases fluid.
9. Review biophysical profiles. Pg 772 What is it used for?
 8-10 normal score
 5 things: US breathing, gross movement, tone, AFI, then FHR and NST.
 Physical exam of the fetus including VS.
10. What are some complications of having an amniocentesis?
 Maternal: PROM, hemorrhage, infection, amniotic fluid embolism, abruptio
placentae, Rh isoimmunization
 Fetal: death, hemorrhage, infection, direct injury, miscarriage, preterm labor,
leakage of amniotic fluid.
 Assess for 1 hour after, tell them about what to look for, Rh type for Rhogam
needs,
11. What is an AFP? Just know the basics! There is a longer description on page 777.
 Alfafetoprotein. High levels confirm diagnosis of an NTD such as spina bifida or
anencephaly or an abdominal wall defect such as omphalocele.
12. What’s chorionic villi sampling?
 CVS: between 10-12 weeks and involves the removal of a specimen from the
fetal portion of the placenta.
13.What is PUBS for?
 percutaneous umbilical blood sampling
 can use for transfusion, inherited blood disorders, karyotyping of malformed
fetuses, detection of fetal infection, IUGR.
 Cordocentesis
14. What’s a nonstress test (NST)? What would be a good result?
 Movements of baby through 20 minute
 Kid is alive and neurologically intact and how much reserve the baby has!
 Reactive, equivocable, non-reactive
 2+ accelerations of 15 bpm for 15 seconds in 20 min
15. What is vibroacoustic stimulation?  Tests FHR response and used in conjunction with NST.
 Reactive if immediate and sustained increase in variability and HR accelerations.
16. What’s a contraction stress test (CST)? What two methods are used? What would be a
good result?
 stimulate baby, don’t want late decels.
 Pitocin and nipple stimulation
 Negative is good. No late decels, with minimum of 3 uterine ctx lasting 40-60 sec
within 10 minute period.
17. What’s a student stress test (SST)? (just kidding!!)