Repro 11 - Pregnancy Part 1

Question 1

What are the fetal components of the placenta? What do each contain and do?

Answer 1

Cytotrophoblast: Inner layer, contains stem cells, core of chorionic villi. Syncytiotrophoblast: multinucleated outer layer, secretes Beta-hCG, transport of gases, nutrients, wastes. “Synch’s w/ the mom”

Question 2

What are the maternal components of the placenta? What do each contain and do?

Answer 2

Decidua basalis: base layer of endometrium

Question 3

Describe the umbilical cord.

Answer 3

Contains 3 vessels and blood flow is reversed from what is expected: 2 umbilical arteries which return deoxygenated blood back to the placenta; they come off from the fetal internal iliac arteries. 1 umbilical vein that brings oxygenated blood from the placenta and drains into the fetal inferior vena cava.

Question 4

What is Urachus? What is patent urachus?

Answer 4

Urachus: connects fetal bladder to yolk sac. Patent urachus: urachus that did not obliterate, leading to urine discharge from the umbilicus.

Question 5

What is a vesicourachal diverticulum And how is it formed?

Answer 5

An outpouching of the bladder caused by a urachus that only partially obliterated. If it did not obliterate at all, then it’s called a patent urachus (urine from umbilicus).

Question 6

What is the Vitelline duct? What happens when it fails to obliterate?

Answer 6

It connects fetal midgut to yolk sac. Failure to obliterate causes fistula to umbilicus, causing Meckel diverticulum.

Question 7

How long is normal term gestation? What is the average gestation? What is the age of viability?

Answer 7

Term gestation: 37-42 weeks. Average gestation is 40 weeks. Age of viability is 24 weeks.

Question 8

How do we diagnose pregnancy? How long do we have to wait post conception?

Answer 8

Blood in 1 week. Urine in 2 weeks.

Question 9

What is the G#P#A#?

Answer 9

G=gravidity: number of pregnancies (includes spontaneous miscarriage, elective abortions, fetal deaths). P= parity: number of deliveries above week 20. A= abortions: number of deliveries below week 20.

Question 10

What is the difference b/w nulliparous vs nulligravida?

Answer 10

Nulliparous: Never delivered. Nulligravida: Never been pregnant.

Question 11

What is the difference b/w primiparious vs primigravid?

Answer 11

Primiparous: had one delivery. Primigravid: 1st pregnancy.

Question 12

What are 4 cardiovascular changes seen in physiologic change during pregnancy?

Answer 12

Cardiac output increases 30-50%. BP decreases in early pregnancy: nadir at 16-20 wks, return to pre-pregnancy levels by term. Plasma volume increase 50%, RBC volume increases 30%. Increased procoagulation factors, leading to hypercoagulable state.

Question 13

What is the cause of Physiologic anemia of pregnancy?

Answer 13

There is an 50% increase of plasma volume but only 30% in RBC volume. Evolution understood that the biggest risk in delivery is bleeding, so even if that happens, the mother can quickly recover.

Question 14

What respiratory changes are seen in normal pregnancy and why is it beneficial?

Answer 14

There is an increase in minute ventilation, causing decrease in PACO2 and PaCO2, mild respiratory alkalosis and this causes CO2 transferred more easily from fetus to mother.

Question 15

Why is there an increase in peripheral resistance to insulin during normal pregnancy?

Answer 15

It is due to human placental lactogen (it shunts nutrient to the fetus), and this worsens thru pregnancy, causing hyperinsulinemia, hyperglycemia, hyperlipidemia.

Question 16

What happens if mother is Rh (-) while the fetus is Rh (+)?

Answer 16

She can develop anti-Rh antibodies if exposed to fetal blood: In the next pregnancy, the IgG Ab can cross the placenta and attack fetal RBCs if Rh (+), leading to hemolytic anemia.

Question 17

What is RhoGAM and when is it used?

Answer 17

An Anti-Rh IgG. For Rh(-) negative mothers that have Rh (+) fetus. Always use during 3 trimester (Irriguardless of bleeding), time of miscarriage, and always after delivery.

Question 18

What is contained in a triple screen Of prenatal testing? In a quad screen?

Answer 18

Triple screen: AFP, hCG, Estriol. The addition of Inhibin A makes it a quad screen.

Question 19

How would the prenatal triple screen come up in a fetus w/ Trisomy 21?

Answer 19

Decreased AFP. Decreased Estriol. Increased hCG.

Question 20

How would the prenatal triple screen come up in a fetus w/ Trisomy 18?

Answer 20

All markers going to be decreased: AFP, Estriol, hCG.

Question 21

What things would cause an increase in AFP in prenatal screening?

Answer 21

Neural tube defects. Abdominal wall defects. Multiple gestations.

Question 22

What is the most common cause of abnormal serum screen?

Answer 22

Incorrect dating.

Question 23

What are the five indications for amniocentesis?

Answer 23

Abnormal maternal serum triple/quad screen. High risk for trisomy or other genetic defects (above 35y.o, carrier of AR disease). Evaluation of fetal lung maturity (lecithin;sphingomyelin ration above 2.0). In Rh-sensitized pregnancy to detect fetal blood type or fetal hemolysis. Testing for infection/

Question 24

When can amniocentesis be performed for genetic evaluation? For fetal lung maturity evaluation?

Answer 24

For genetic evaluation: 15-17 weeks. For fetal lung maturity: 3rd trimester.

Question 25

What is Chorionic Villus Sampling (CVS)? What are strengths and weaknesses with this procedure?

Answer 25

Take a sample from the placenta. Strengths: Performed at 10-12 weeks. Weakness: inability to diagnose Neural Tube Defects, can cause limb defects if done earlier than 9 weeks, 1% fetal loss.

Question 26

What happens when division of the zygote occurs prior to morula stage (within 3 days of fertilization)?

Answer 26

Diamniotic/dichorionic placentation.

Question 27

What happens when division of the zygote occurs in the blastocyst stage (4-8 days post-fertilization)?

Answer 27

Diamniotic/monochorionic placentation.

Question 28

What happens when division of the zygote occurs 8-12 days after fertilization (during the formation of embryonic disc w/epiblast/hypoblast)?

Answer 28

Monochorionic, Monoamniotic.

Question 29

What happens when division of the zygote occurs 13 days after fertilization?

Answer 29

Conjoined twins

Question 30

What is the most common place to be conjoined in conjoined twins?

Answer 30

At the chest.

Question 31

What does it mean when in ultrasound you find 1 yolk sac and 2 fetal poles?

Answer 31

Monoamnionicity.

Question 32

What does it mean when in ultrasound you find two embryos with cord entanglement?

Answer 32

Monoamnionicity.

Question 33

What is the Twin-Twin transfusion syndrome?

Answer 33

Seen most often in monoamniotic/monochorionic twins, this can ONLY occur in monochorionicity. It is when an anastomosis (classically AV) leads of shunting of the blood; the donor baby sends more blood into the other, leaving it the donor anemic, pale, growth restricted. The recipient is polycythemic, plethoric, overloaded, and heart failure (the recipient does worse than donor).

Question 34

An infant is noted to have a persistently wet umbilicus. What is the cause?

Answer 34

Patent urachus.

Question 35

How do cardiac output and plasma volume change during pregnancy?

Answer 35

CO increases 30-50%. Plasma volume increases 50%.

Question 36

What are some of the causes of an elevated AFP on maternal serum screening?

Answer 36

Neural tube defect. Multiple gestation. Abdominal wall defect. Incorrect dating.

Question 37

Monozygotic twins are delivered. One is pale and has a hematocrit of 15% and the other is flushed w/ a hematocrit of 55%. What is the cause of these features?

Answer 37

Twin-Twin transfusion.