OB Gyn Case Files Cases 7-12 Flashcards
What’s the MC causes of abnormal serum screening tests? What should you do?
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
What’s the msAFP cutoff?
2.0 or 2.5 MOM (multiples of the median)
At 16 wks gestation, where would the fundus be located? 20 weeks?
16 wks: midway btwn symphysis pubis and umbilicus
20 wks: level of umbilicus
What’s alfa-fetoprotein and what’s it analogous to?
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
What’s frist trimester screening? When can it be done?
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
What’s neural tube defects and what can it lead i?
failure of embryonic neural fold closure leads to absent cranium & cerebral hemispheres (anencephaly) or nonclosure of vertebral arches (spina bifida)
What tests are done for second trimester screening? When do you do it?
msAFP, hCG, inhibin-A, unconjugated estriol
Btwn 15-21 weeks gestation
What are some causes of elevated msAFP?
neural tube defects, underestimation of gestational age, multiple gestations, abdominal wall defects, cystic hygroma, fetal skin defects, sacrococcygeal teratoma, decreased maternal weight, oligohydramnios
What are the screening serums for a pt with trisomy 21?
decreased AFP, unconjugated estriol (uE3), PAPP-A
increased hcG and inhibin A
Would also have thickened nuchal translucency
What are the screening serums for a pt with trisomy 18?
Decreased AFP, unconjugated estriol (uE3), hCG, PAPP-A
Inhibin: N/A
What are the screening serums for a pt with trisomy 13?
Decreased PAPP-A and B-hCG
What are some causes of low msAFP?
overestimation of gestational age, chromosomal trisomies, molar pregnancy, fetal death, increased maternal weight
What are some US findings for a pt with down syndrome?
thickened nuchal fold, shortened femur length, or echogenic bowel
What can an amniocentesis be used for in elevated msAFP?
Test amniotic fluid for AFP, can also obtain fetal karyotype to identify fetal aneuploidy
What’s MPSS?
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)
Name some teratogens
Androgens, alcohol, phenytoin (dilantin), lithium carbonate, methotrexate, retinoic acid (vit A), ACEi, warfarin, valproic acid, carbazepine
What effects do androgens have on embryo?
teratogen that can cause masculinization of female fetus and labial fusion
what effects does alcohol have on an embryo?
fetal alcohol syndrome, IUGR, microcephaly
What effects does phenytoin (dilantin) have on an embryo?
fetal hydantoin syndrome, IUGR, micocephaly, facial defects
What effects does lithium carbonate have on an embryo?
heart and great vessel defects (epstein anomaly)
What effects does methotrexate have on an embryo?
skeletal defects, limb defects
What effects does retinoic acid (vit A) have on an embryo?
facial defects, neural tube defects
What effects does ACEi have on an embryo?
skull anomalies, limb defects, miscarriage; renal tubule dysgenesis, renal failure in neonate, oligohydramnios
What effects does warfarin have on an embryo?
CNS and skeletal defects
What effects does valproic acid and carbamazepine have on an embryo?
neural tube defects
What’s a teratogen’s effect in the first 2 weeks of gestation?
All of nothing effect - embryo is killed or recovers from the exposure
when could malformation occur from teratogen exposure?
during organogenesis - days 15-60
Pregnancies with elevated msAFP which after eval are unexplained are at an increased risk for what?
stillbirth, growth restriction, preeclampsia and placental abruption
What are some maternal effects of pregnancy with twin gestation?
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
What are twin gestations without a dividing membrane at a higher rate for and why?
stillbirth due to cord entanglement
Does mono or dizygotic twins have a higher rate of anomalies and maternal complications?
mono
What’s velamentous cord insertion?
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
What’s vasa previa?
umbilical vessels that aren’t protected by cord or membranes that cross internal cervical os in front of the fetal presenting part
With what does vasa previa MC occur with?
velamentous cord insertion or placenta w/ one or more accessory lobes
what do you call a placenta w/ 1+ accessory lobes?
bilobed or succenturiate-lobed placenta
how does monozygot twins form?
1 egg, 1 sperm
how does dizygotic twins form?
2 eggs, 2 sperm
what’s chorionicity? what’s it in monozygotic and dyzgotic twins
the number of placentas
Monozygotic: can be monochorionic or dichorionic
Dyzygotic: always dichorionic
what’s amnionicity? What’s it in monozygotic and dyzgotic twins?
the number of amniotic sacs
Monozygotic twins can be monoamnionic or diamniotic
Dyzgotic: always diamniotic
what are potential complications of twin gestation?
higher rate of congenital malformations, preeclampsia, postpartum hemorrhage and twin-twin transfusion (TTT) syndrome
When did monochoronic/diamniotic twins division occur?
Day 4-8
when did monochorionic/monoamniotic twins dvision occur?
Day 8-12
when did conjoined twins division occur?
after day 12
How does clomiphene increase chance of multiple gestations?
induces ovulation and promotes that maturation of multiple follicles increasing the number of eggs released during ovulation and available for fertilization
what are some fetal or placental complications during twins?
preterm delivery, IUGR, polyhydramnios, stillbirth, fetal anomalies, plcenta previa, abruption, twin-twin transufsion syndrome
What’s twin-twin transfusion (TTT) syndrome?
one twin’s the donor, other is recipient. One’s larger w/ more amniotic fluid and other’s smaller with oligohydroamnios
How do you treat TTT syndrome?
laser ablation of shared anastomotic vessels (dont at special centers) or serial amniocentesis for decompression
What are risk factors for vasa previa?
bilobed/succenturiate-lobed or low-lying placenta, multifetal pregnancy, and pregnancy resulting from in vitro
How do you identify vasa previa and what’s the proper treatment?
Color doppler ultrasound
Tx: planned C-section before ROM around 35-36 wks of gestation
What’s a contraindicated test if someone has vasa previa?
digital vaginal exam
How can you differentiate fetal from maternal blood?
Apt test and Kleihauer-Betke test
What’s prodromal symptoms of HSV outbreak?
burning, itching or tingling of the perineal region prior to the classical vesicles
What’s the biggest risk for a fetus born to a mom w/ HSV? How can you decrease this risk?
neonatal encephalitis
Decrease risk by delivering via C-section
Which type of HSV usually causes gential warts and how do you treat it?
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
What’s chancroid and what causes it?
STD caused by GN bacterium H. ducreyi, causes painful genital vulvar lesions
How does syphillis typically present?
first stage: small, round, painless chancre in area exposed to spirochete
what’s antepartum vaginal bleeding?
vaginal bleeding occurring after 20 weeks gestation
What’s complete placenta previa? how do you diagnose it?
placenta completely covers the internal os of the uterine cervix
diagnose it via US
what’s placenta abruption? what’s it assoc w/?
premature separation of the placenta
Assoc w/ painful uterine contractions or excess uterine tone
what would h/o postcoital spotting in pregnancy be a sign of?
possible placenta previa
What’s the best treatment for someone with placenta previa?
expectant mangagment if hemodynamically stable and norm fetal HR, delivery via C-section at or after 34 weeks
What are the types of placenta previa?
- complete
- marginal
- parital
- low-lying placentation
what’s partial placenta previa?
placenta partially covers the internal cervical os
what’s marginal placenta previa?
placental abuts against the internal oss of the cervix
what’s low-lying placenta?
edge of the placenta is w/in 2-3 cm of the internal cervical os
what are the 2 MC causes of significant antepartum bleeding?
placenta abruption and placenta previa
what are some risk factors for placenta previa?
gran multiparity, prior c-section delivery, prior uterine curettage, previous placenta previa, multiple gestation
what’s placenta accreta? What is it MC with?
invasion of the placenta into the uterus
MC w/ placenta previa esp with uterine scar after c-section
What does painless antepartum vaginal bleeding suggestion?
placenta previa
When placenta previa is diagnozed early in gestation (like second trimester) what’s the next move?
repeat US later because the placenta can transmigrate away from the cervix
