A 32-year-old woman, gravida 2 para 1, at 30 weeks gestation comes to the emergency department 30 minutes after a gush of clear fluid from the vagina. The patient initially thought she was leaking urine but leakage continued after voiding. She reports occasional contractions but no fever, chills, or vaginal bleeding. Fetal movements are normal. This pregnancy has been complicated by iron deficiency anemia requiring a prenatal vitamin and iron supplementation. She has no chronic medical conditions and has had no surgeries. The patient's previous pregnancy ended in an uncomplicated term vaginal delivery. She does not use tobacco, alcohol, or illicit drugs. The patient owns a bakery, where she works 12-14 hours a day and often lifts heavy objects. Temperature is 36.7 C (98.1 F), blood pressure is 98/60 mm Hg, and pulse is 78/min. BMI is 28 kg/m2. The fetal heart rate is 150/min with moderate variability and no decelerations. Tocometry reveals no contractions. The abdomen is nontender. Sterile speculum examination reveals a large pool of clear fluid that is nitrazine positive, and the cervix appears to be 1 cm dilated. Urinalysis shows trace protein. Transabdominal ultrasound reveals a fetus in transverse lie and an amniotic fluid index of 5 cm. Which of the following is the most likely complication of this patient's presentation?
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Preterm premature rupture of membranes (PPROM) is membrane rupture (eg, leakage of fluid) at <37 weeks gestation with no associated contractions. Clinical features include a gush of clear fluid, a pool of nitrazine-positive vaginal fluid on speculum examination that "ferns" on microscopy, and oligohydramnios. Risk factors include physical exertion (eg, heavy lifting), anemia, first-trimester bleeding, and a history of PPROM in a prior pregnancy.
Patients with PPROM are at risk for umbilical cord prolapse, which occurs when the cord descends past the presenting fetal part (part closest to the maternal pelvis) and protrudes through the cervix and into the vagina. Umbilical cord prolapse is an obstetric emergency; compression of the prolapsed umbilical cord by the fetus can impede blood flow and cause fetal hypoxia. Clinical features of umbilical cord prolapse include fetal heart rate abnormalities (eg, recurrent variable decelerations, bradycardia); diagnosis is confirmed by palpating a pulsatile umbilical cord in the vagina or cervix. Management includes elevation of the presenting fetal part to prevent compression of the umbilical cord and emergency cesarean delivery. Other complications of PPROM include chorioamnionitis, preterm delivery, and abruptio placentae.
(Choice A) Placenta accreta occurs when placental villi attach directly to the myometrium rather than to the uterine decidua. Risk factors include prior cesarean delivery or uterine surgery (eg, myomectomy, curettage) and placenta previa. PPROM does not increase the risk of placenta accreta as placental implantation is complete by the start of the second trimester.
(Choice B) Preeclampsia is not associated with PPROM. This patient is normotensive, and the proteinuria is likely due to amniotic fluid contaminating the urine sample.
(Choice C) Renal agenesis is a cause, rather than a complication, of oligohydramnios.
(Choice E) Risk factors for uterine rupture include prior uterine surgery (eg, cesarean delivery, myomectomy), trauma, macrosomia, and abnormal placentation. PPROM does not increase the risk of uterine rupture.
Educational objective:
Preterm premature rupture of membranes can be complicated by umbilical cord prolapse, an obstetric emergency. Umbilical cord prolapse is managed by relieving the cord compression and performing an emergency cesarean delivery.