A 27-year-old woman, gravida 2, para 1, at 31 weeks gestation is evaluated in the labor an… — USMLE Step 2 CK

A $27$ -year-old woman, gravida $2$ , para $1$ , at $31$ weeks gestation is evaluated in the labor and delivery unit for chills and a rapid heart rate. She was admitted $48$ hours ago after presenting with a sudden gush of clear vaginal fluid. Ferning and nitrazine tests were positive at that time. Upon admission, she received her first dose of intramuscular betamethasone and was started on prophylactic intravenous ampicillin and oral azithromycin. Her temperature is $39.1^\circ\text{C}$ ( $102.4^\circ\text{F}$ ), blood pressure is $112/72$ mmHg, pulse is $118$ /min, and respirations are $18$ /min. Continuous fetal monitoring shows a baseline heart rate of $175$ /min with moderate variability and no decelerations. Physical examination reveals a tender uterine fundus and malodorous fluid pooling in the posterior vaginal fornix. The cervix is $2$ cm dilated and $50\%$ effaced, with the fetal vertex at $-2$ station. Which of the following is the most appropriate next step in management?

Initiation of intravenous ampicillin and gentamicin followed by oxytocin-induced vaginal deliveryAnswer
B
Initiation of intravenous ampicillin and gentamicin followed by urgent cesarean delivery
C
Administration of a second dose of intramuscular betamethasone and maintenance of expectant management
D
Intravenous hydration and continued observation, as maternal tachycardia is a normal physiologic response in the third trimester
E
Transition to intravenous vancomycin and piperacillin-tazobactam while awaiting the onset of spontaneous labor

Answer

Initiation of intravenous ampicillin and gentamicin followed by oxytocin-induced vaginal delivery

This patient has preterm premature rupture of membranes (PPROM) complicated by intra-amniotic infection (chorioamnionitis), indicated by her fever, maternal tachycardia, fetal tachycardia, uterine tenderness, and malodorous amniotic fluid. The standard of care for clinically diagnosed intra-amniotic infection, regardless of gestational age, is prompt administration of therapeutic intravenous antibiotics (typically ampicillin and gentamicin) and immediate delivery. Because there are no standard obstetric indications for a cesarean delivery in this vignette (the fetal heart rate tracing is reassuring with moderate variability and no decelerations), vaginal delivery via oxytocin induction is the safest and most appropriate route.

Step-by-Step Solution

Evaluate the patient's current clinical presentation.

The patient has a fever (

39.1^\circ\text{C}

), maternal tachycardia (

118

/min), fetal tachycardia (

175

/min), uterine tenderness, and malodorous amniotic fluid.

Identifying these signs is required to diagnose intra-amniotic infection (chorioamnionitis) in a patient with a history of preterm premature rupture of membranes (PPROM).

Determine the definitive treatment for the identified complication.

The standard of care for chorioamnionitis is prompt administration of therapeutic intravenous antibiotics and immediate delivery, regardless of gestational age.

Continuing expectant management after clinical infection sets in risks maternal sepsis, septic shock, and severe fetal neurologic or infectious morbidity.

Select the appropriate route of delivery.

Vaginal delivery via oxytocin induction is chosen.

Chorioamnionitis is not a primary indication for a cesarean delivery. Because the fetal heart rate tracing is reassuring (moderate variability, no decelerations), vaginal delivery is the safest route and minimizes maternal surgical risks.

Key Concept

Management of Chorioamnionitis complicating PPROM

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