Fetal Development

Question 1

Progression of Embryonic Development

Answer 1

Zygote > Morula > Blastocyst

Question 2

Where and when does implantation occur

Answer 2

Most common: Upper posterior wall of uterus

Timing: 1 week

Question 3

Nagele’s Rule

Answer 3

Add 7d to LMP, subract three months

Question 4

When does the fetal Heartbeat Begin

Answer 4

3 weeks

Question 5

When do the amnion and chorion fuse?

Answer 5

14 weeks

Question 6

Primary source of progesterone

Answer 6

Maternal LDL

Question 7

Primary source of estrogen in prengnacy

Answer 7

Fetal Adrenal Gland

Question 8

What type of placenta is the human placenta?

Answer 8

Hemochorioendothelial (only other mammal with this type is guinea pig)

Question 9

Produces progesterone for first 6-7 weeks

Answer 9

Corpus Luteum

Question 10

Layer absent in Placenta Accreta

Answer 10

Nitabuch layer of fibrinoid degeneration

Question 11

Placental abnormality associated with IUGR

Answer 11

Circumvallate placenta

Question 12

Placentomegaly

Answer 12

Syphilis, Isoimmunization/hydrops, DM

Question 13

Placental Sulfatase Deficiency

Answer 13

X-linked
Decreased estrogen
Associated with prolonged gestation and icthyosis in affected males

Question 14

Placental Aromatase Deficiency

Answer 14

Aromatase converts androstenedione to estrogen

May lead to virilization of mother and female fetus

Question 15

Vascular Placental Mass

Answer 15

Chorangioma
May function as AV shunt and cause Hydrops
Follow serial ultrasounds

Question 16

Path of Fetal RBC

Answer 16

Placenta > Umbilical vein > Ductusu venosus > IVC > Right Atrium > Foramen Ovale > Left atrium > Left ventricle > Aorta > Ductus arteriosus > CAs and brain

Deoxygenated blood > SVC and IVC > R Atrium > Right ventricle

Question 17

Most common type of conjoined twins

Answer 17

Thoracophagus

Question 18

Zygosity

Answer 18

70% Dizygotic
30% Monozygotic
(2/3 MCDA, 1/3 DCDA)

Question 19

Interlocking twince

Answer 19

Breech/Vertex (interlocking Chins)

Question 20

TTTS

Answer 20

25% of MCDA pregnancies, severe in 15%
2/2 AV anastomosis
- Monochorionic Placentation
- Poly-Oli sequence
- Discordance > 20%

Question 21

Quintero Staging

Answer 21

Stage I: Poly/Oli sequence
Stage II: Poly/Oli, no bladder seen, Normal Dopplers
Stage III: Abnormal doppers (absent/reversed ED flow in UA, or pulsatile flow in umbilical vein)
Stage IV: Hydrops
Stage V: Fetal Death

Question 22

TTTS Treatment

Answer 22

26 weeks:
Stage II-IV: Serial Amnio

Deliver by 37 weeks

Question 23

TRAP Sequence

Answer 23

Twin Reversed Arterial Perfusion Sequence

• Acardiac Twin
• 2/2 Paired artery-to-artery and vein-to-vein anastomoses