premature rupture of membranes

PROM results from a combination of mechanical stress and biochemical weakening of the fetal membranes, often due to subclinical infection/inflammation (e.g., chorioamnionitis), which triggers proteases (matrix metalloproteinases) that degrade collagen in the amniotic membrane. Risk factors include prior PROM, intra-amniotic infection, smoking, low socioeconomic status, cervical insufficiency, multiple gestation, polyhydramnios, and vaginal bleeding in pregnancy.

Clinical presentation: sudden gush of clear or blood-tinged fluid from the vagina, or continuous leaking. Diagnosis is made via sterile speculum exam showing pooling of fluid in the posterior fornix, nitrazine paper turning blue (alkaline amniotic fluid, pH >6.5, vs acidic vaginal pH), and arborization/ferning pattern on microscopy when fluid dries on a slide. Ultrasound may show oligohydramnios. Avoid digital cervical exams to reduce infection risk until labor is anticipated.

Management depends on gestational age: - Term PROM (≥37 weeks): Induce labor if not spontaneous within a reasonable time to reduce infection risk (e.g., GBS-related chorioamnionitis). - Preterm PROM (PPROM, <37 weeks): Management balances risks of prematurity vs. infection/cord prolapse/abruption. Generally: hospitalize, administer latency antibiotics (e.g., ampicillin + azithromycin) to prolong pregnancy and reduce infection, corticosteroids to accelerate fetal lung maturity if <34 weeks, magnesium sulfate for neuroprotection if <32 weeks, and GBS prophylaxis if indicated. Deliver if there are signs of chorioamnionitis, non-reassuring fetal status, or advancing gestational age (typically at 34 weeks per ACOG unless complications dictate earlier delivery).

Complications: chorioamnionitis, umbilical cord prolapse or compression, placental abruption, neonatal respiratory distress syndrome, pulmonary hypoplasia (if prolonged oligohydramnios especially in early second trimester), and sepsis.

High-yield boards points: distinguish PROM from PPROM by gestational age; nitrazine and ferning tests are classic diagnostic tools; the main goal in PPROM management is prolonging pregnancy while monitoring for infection; corticosteroids and antibiotics are cornerstone therapies in preterm cases.