Master the board step 3

Master the Boards: USMLE Step 3
Answer: E. Although emergency cerclage (vaginal or abdominal) is indicated in women
who present with cervical dilation in the absence of labor or abruption, it can only be
performed when chorioamnionitis is first ruled out. Tocolysis is not appropriate in management
of cervical insufficiency. Prophylactic antibiotics and tocolytics are not recommended.
Risk factors for cervical insufficiency are a history of any of the following:
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Second-trimester abortion
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Cervical laceration during delivery
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Deep cervical conization
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Diethylstilbestrol (DES) exposure
Cervical Cerclage:
••
Performed at 14–16 weeks
••
Suture encircles cervix
to prevent cervical canal
from dilation
••
Indicated electively or
emergently in cervical
insufficiency
Treatment
··
Perform elective cerclage placement at 13–16 weeks’ gestation for patients
with ≥ 3 unexplained midtrimester pregnancy losses.
··
Only perform urgent cerclage after first ruling out labor and chorioamnionitis.
··
Perform cerclage removal at 36–37 weeks, after fetal lung maturity.
What is the next step in management of an asymptomatic woman with no prior history
of preterm labor, found to have short cervix on routine transvaginal ultrasound
before 16–20 weeks?
Answer: Transvaginal ultrasound surveillance to evaluate for persistent cervical shortening,
and to evaluate for changes in cervical dilation; however, cerclage is not indicated
unless dilation is present and chorioamnionitis or signs of labor are not present. Repeat
the exam after 20 weeks if short cervix is still present.
Disproportionate Fetal Growth
Intrauterine Growth Restriction (IUGR)
··
IUGR is the diagnosis when the estimated fetal weight (EFW) is < 5−10 percentile
for gestational age or < 2,500 g (5 lb, 8 oz). Accurate, early pregnancy
dating is essential for making the diagnosis.
··
An early sonogram (< 20 weeks) is the next step in management if accurate
dates are not known.
··
Never change the gestational age based on a late sonogram.
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