OB Gyn Case Files Cases 7-12

Question 1

What’s the MC causes of abnormal serum screening tests? What should you do?

Answer 1

wrong dates or multiple gestations
Do an ultrasound! If still abnormal and 16 wks, repeat soon, if 20 wks - genetic counseling and referral for amniocentesis

Question 2

What’s the msAFP cutoff?

Answer 2

2.0 or 2.5 MOM (multiples of the median)

Question 3

At 16 wks gestation, where would the fundus be located? 20 weeks?

Answer 3

16 wks: midway btwn symphysis pubis and umbilicus

20 wks: level of umbilicus

Question 4

What’s alfa-fetoprotein and what’s it analogous to?

Answer 4

gylcoprotein made first by the fetal yolk sac then later by the fetal liver and GI tract. It deffuses thru the chorioamniotic membranes
analogous to adult albumin

Question 5

What’s frist trimester screening? When can it be done?

Answer 5

Biochemical markers: PAPP-A & B-hCG +/- transvaginal US to measure posterior neck (nuchal translucency) to give risk of down syndrome & trisomy 18
10-13 wks gestation

Question 6

What’s neural tube defects and what can it lead i?

Answer 6

failure of embryonic neural fold closure leads to absent cranium & cerebral hemispheres (anencephaly) or nonclosure of vertebral arches (spina bifida)

Question 7

What tests are done for second trimester screening? When do you do it?

Answer 7

msAFP, hCG, inhibin-A, unconjugated estriol

Btwn 15-21 weeks gestation

Question 8

What are some causes of elevated msAFP?

Answer 8

neural tube defects, underestimation of gestational age, multiple gestations, abdominal wall defects, cystic hygroma, fetal skin defects, sacrococcygeal teratoma, decreased maternal weight, oligohydramnios

Question 9

What are the screening serums for a pt with trisomy 21?

Answer 9

decreased AFP, unconjugated estriol (uE3), PAPP-A
increased hcG and inhibin A
Would also have thickened nuchal translucency

Question 10

What are the screening serums for a pt with trisomy 18?

Answer 10

Decreased AFP, unconjugated estriol (uE3), hCG, PAPP-A

Inhibin: N/A

Question 11

What are the screening serums for a pt with trisomy 13?

Answer 11

Decreased PAPP-A and B-hCG

Question 12

What are some causes of low msAFP?

Answer 12

overestimation of gestational age, chromosomal trisomies, molar pregnancy, fetal death, increased maternal weight

Question 13

What are some US findings for a pt with down syndrome?

Answer 13

thickened nuchal fold, shortened femur length, or echogenic bowel

Question 14

What can an amniocentesis be used for in elevated msAFP?

Answer 14

Test amniotic fluid for AFP, can also obtain fetal karyotype to identify fetal aneuploidy

Question 15

What’s MPSS?

Answer 15

Massively parallel shotgun sequencing which analyzes and amplifies cell free fetal DNA (cffDNA) in matneral blood btwn 10-22 wks gestation to detect excessive fetal chromosomes (trisomy 21,18,13)

Question 16

Name some teratogens

Answer 16

Androgens, alcohol, phenytoin (dilantin), lithium carbonate, methotrexate, retinoic acid (vit A), ACEi, warfarin, valproic acid, carbazepine

Question 17

What effects do androgens have on embryo?

Answer 17

teratogen that can cause masculinization of female fetus and labial fusion

Question 18

what effects does alcohol have on an embryo?

Answer 18

fetal alcohol syndrome, IUGR, microcephaly

Question 19

What effects does phenytoin (dilantin) have on an embryo?

Answer 19

fetal hydantoin syndrome, IUGR, micocephaly, facial defects

Question 20

What effects does lithium carbonate have on an embryo?

Answer 20

heart and great vessel defects (epstein anomaly)

Question 21

What effects does methotrexate have on an embryo?

Answer 21

skeletal defects, limb defects

Question 22

What effects does retinoic acid (vit A) have on an embryo?

Answer 22

facial defects, neural tube defects

Question 23

What effects does ACEi have on an embryo?

Answer 23

skull anomalies, limb defects, miscarriage; renal tubule dysgenesis, renal failure in neonate, oligohydramnios

Question 24

What effects does warfarin have on an embryo?

Answer 24

CNS and skeletal defects

Question 25

What effects does valproic acid and carbamazepine have on an embryo?

Answer 25

neural tube defects

Question 26

What's a teratogen's effect in the first 2 weeks of gestation?

Answer 26

All of nothing effect - embryo is killed or recovers from the exposure

Question 27

when could malformation occur from teratogen exposure?

Answer 27

during organogenesis - days 15-60

Question 28

Pregnancies with elevated msAFP which after eval are unexplained are at an increased risk for what?

Answer 28

stillbirth, growth restriction, preeclampsia and placental abruption

Question 29

What are some maternal effects of pregnancy with twin gestation?

Answer 29

increased N/V, > physiological anemia, > increased of BP after 20 wks, > increase in size and weight of uterus, increased DVT, postpartum hemorrhage, need for C-section, gestational diaetes, preeclampsia

Question 30

What are twin gestations without a dividing membrane at a higher rate for and why?

Answer 30

stillbirth due to cord entanglement

Question 31

Does mono or dizygotic twins have a higher rate of anomalies and maternal complications?

Answer 31

mono

Question 32

What's velamentous cord insertion?

Answer 32

umbilical vessels separate before reaching the placenta, protected by a thin fold of amnion instead of by the cord or placenta itself these vessels are susceptible to tearing after rupture of membrane

Question 33

What's vasa previa?

Answer 33

umbilical vessels that aren't protected by cord or membranes that cross internal cervical os in front of the fetal presenting part

Question 34

With what does vasa previa MC occur with?

Answer 34

velamentous cord insertion or placenta w/ one or more accessory lobes

Question 35

what do you call a placenta w/ 1+ accessory lobes?

Answer 35

bilobed or succenturiate-lobed placenta

Question 36

how does monozygot twins form?

Answer 36

1 egg, 1 sperm

Question 37

how does dizygotic twins form?

Answer 37

2 eggs, 2 sperm

Question 38

what's chorionicity? what's it in monozygotic and dyzgotic twins

Answer 38

the number of placentas Monozygotic: can be monochorionic or dichorionic Dyzygotic: always dichorionic

Question 39

what's amnionicity? What's it in monozygotic and dyzgotic twins?

Answer 39

the number of amniotic sacs Monozygotic twins can be monoamnionic or diamniotic Dyzgotic: always diamniotic

Question 40

what are potential complications of twin gestation?

Answer 40

higher rate of congenital malformations, preeclampsia, postpartum hemorrhage and twin-twin transfusion (TTT) syndrome

Question 41

When did monochoronic/diamniotic twins division occur?

Answer 41

Day 4-8

Question 42

when did monochorionic/monoamniotic twins dvision occur?

Answer 42

Day 8-12

Question 43

when did conjoined twins division occur?

Answer 43

after day 12

Question 44

How does clomiphene increase chance of multiple gestations?

Answer 44

induces ovulation and promotes that maturation of multiple follicles increasing the number of eggs released during ovulation and available for fertilization

Question 45

what are some fetal or placental complications during twins?

Answer 45

preterm delivery, IUGR, polyhydramnios, stillbirth, fetal anomalies, plcenta previa, abruption, twin-twin transufsion syndrome

Question 46

What's twin-twin transfusion (TTT) syndrome?

Answer 46

one twin's the donor, other is recipient. One's larger w/ more amniotic fluid and other's smaller with oligohydroamnios

Question 47

How do you treat TTT syndrome?

Answer 47

laser ablation of shared anastomotic vessels (dont at special centers) or serial amniocentesis for decompression

Question 48

What are risk factors for vasa previa?

Answer 48

bilobed/succenturiate-lobed or low-lying placenta, multifetal pregnancy, and pregnancy resulting from in vitro

Question 49

How do you identify vasa previa and what's the proper treatment?

Answer 49

Color doppler ultrasound | Tx: planned C-section before ROM around 35-36 wks of gestation

Question 50

What's a contraindicated test if someone has vasa previa?

Answer 50

digital vaginal exam

Question 51

How can you differentiate fetal from maternal blood?

Answer 51

Apt test and Kleihauer-Betke test

Question 52

What's prodromal symptoms of HSV outbreak?

Answer 52

burning, itching or tingling of the perineal region prior to the classical vesicles

Question 53

What's the biggest risk for a fetus born to a mom w/ HSV? How can you decrease this risk?

Answer 53

neonatal encephalitis | Decrease risk by delivering via C-section

Question 54

Which type of HSV usually causes gential warts and how do you treat it?

Answer 54

HSV-2 Tx: oral Acyclovir (covers HSV1 and 2), especially at 26 weeks to decrease viral shedding, decrease duration of lesions and frequency of outbreaks at term

Question 55

What's chancroid and what causes it?

Answer 55

STD caused by GN bacterium H. ducreyi, causes painful genital vulvar lesions

Question 56

How does syphillis typically present?

Answer 56

first stage: small, round, painless chancre in area exposed to spirochete

Question 57

what's antepartum vaginal bleeding?

Answer 57

vaginal bleeding occurring after 20 weeks gestation

Question 58

What's complete placenta previa? how do you diagnose it?

Answer 58

placenta completely covers the internal os of the uterine cervix diagnose it via US

Question 59

what's placenta abruption? what's it assoc w/?

Answer 59

premature separation of the placenta | Assoc w/ painful uterine contractions or excess uterine tone

Question 60

what would h/o postcoital spotting in pregnancy be a sign of?

Answer 60

possible placenta previa

Question 61

What's the best treatment for someone with placenta previa?

Answer 61

expectant mangagment if hemodynamically stable and norm fetal HR, delivery via C-section at or after 34 weeks

Question 62

What are the types of placenta previa?

Answer 62

1. complete 2. marginal 3. parital 4. low-lying placentation

Question 63

what's partial placenta previa?

Answer 63

placenta partially covers the internal cervical os

Question 64

what's marginal placenta previa?

Answer 64

placental abuts against the internal oss of the cervix

Question 65

what's low-lying placenta?

Answer 65

edge of the placenta is w/in 2-3 cm of the internal cervical os

Question 66

what are the 2 MC causes of significant antepartum bleeding?

Answer 66

placenta abruption and placenta previa

Question 67

what are some risk factors for placenta previa?

Answer 67

gran multiparity, prior c-section delivery, prior uterine curettage, previous placenta previa, multiple gestation

Question 68

what's placenta accreta? What is it MC with?

Answer 68

invasion of the placenta into the uterus | MC w/ placenta previa esp with uterine scar after c-section

Question 69

What does painless antepartum vaginal bleeding suggestion?

Answer 69

placenta previa

Question 70

When placenta previa is diagnozed early in gestation (like second trimester) what's the next move?

Answer 70

repeat US later because the placenta can transmigrate away from the cervix