112 Obstetrics and Gynecology Board Review •••
❍ What is perinatal mortality associated with an undiagnosed vasa previa?
60%.
❍ What percentage of vasa previa is detected by antepartum ultrasound?
<10%.
❍ What is the signature of hepatic lesion of preeclampsia?
Periportal necrosis.
❍ When do convulsions occur during eclampsia?
50% before the onset of labor, and the other 50% equally divided between intrapartum and postpartum.
❍ What are the benefits of antepartum corticosteroids in premature babies?
- Increased lung compliance, increased surfactant production, and less respiratory distress syndrome.
- Less intraventricular hemorrhage.
- Less necrotizing enterocolitis.
- Less neonatal mortality.
❍ What are the NIH recommendations for steroid use in preterm premature rupture of membranes?
Recommended for <30 to 32 weeks in the absence of chorioamnionitis.
❍ Of all intrauterine growth restriction (IUGR) babies, how many show symmetric growth lag?
20%.
❍ Of all IUGR babies, how many are affected by a chromosomal abnormality, congenital malformation,
or genetic syndrome?
10%.
❍ What metabolic problems are commonly found in IUGR neonates?
Hypocalcemia, hypoglycemia, hyponatremia, hypothermia, and polycythemia.
❍ At what gestational age, does maternal immunoglobulin G (IgG) begin to crossover the placenta
and provide protection for the fetus?
16 weeks. By 26 weeks fetal and maternal IgG serum levels are similar.
❍ How is Toxoplasma gondii infection diagnosed in the fetus?
Cord blood fetal anti-Toxoplasma IgM, or amniotic fluid polymerase chain reaction.
❍ What percentage of adults in the US has antibodies (and thus immunity) to Toxoplasma?
40% to 50%, and the prevalence is highest in lower socioeconomic populations.