Harvey's Garden

Pre-labor Rupture of Membranes

3 min read

  • Definition
    • Rupture of amniotic sac before the onset of labor.
    • Term PROM: ≥37 weeks gestational age (GA).
    • Preterm PROM (PPROM): <37 weeks GA. PPROM is associated with ~40% of preterm deliveries.
  • Risk Factors
    • Prior PPROM
    • Genital tract infection (e.g., bacterial vaginosis, chorioamnionitis).
    • Antepartum bleeding.
    • Smoking.
    • Low socioeconomic status, low BMI.
    • Multiple gestation, polyhydramnios (uterine overdistention).
  • Clinical Presentation & Diagnosis
    • Hx: Patient reports a sudden “gush” or steady leakage of clear or pale-yellow fluid from the vagina.
    • AVOID digital vaginal exam unless delivery is imminent, as it increases infection risk. Perform a sterile speculum exam instead.
    • Dx Confirmation:
      • Pooling: Visualization of amniotic fluid in the posterior vaginal fornix.
      • Nitrazine Test: Paper turns blue (pH >6.5-7.0) indicating alkaline amniotic fluid (normal vaginal pH is 3.8-4.5). False positives can occur with blood or semen.
      • Fern Test: Amniotic fluid forms a “ferning” pattern when dried on a glass slide and viewed under a microscope.
      • Ultrasound: May show oligohydramnios (low amniotic fluid).
  • Management by Gestational Age
    • Immediate delivery is indicated at any GA if there are signs of maternal/fetal compromise (e.g., chorioamnionitis, placental abruption, non-reassuring fetal status).
    • Term (≥37 weeks):
      • Proceed to delivery, typically via induction of labor (e.g., with oxytocin) to reduce infection risk.
      • Administer GBS prophylaxis if status is positive or unknown.
    • Late Preterm (34 0/7 to 36 6/7 weeks):
      • Proceed to delivery.
      • ACOG recommends a single course of corticosteroids if the patient has not received them previously and delivery is not immediate.
      • GBS prophylaxis as indicated.
    • Preterm (24 0/7 to 33 6/7 weeks):
      • Expectant management is recommended in a hospital setting.
      • Latency Antibiotics: A 7-day course (e.g., IV ampicillin/erythromycin followed by oral amoxicillin/erythromycin) is given to prolong latency and reduce maternal/neonatal infection.
      • Antenatal Corticosteroids: A single course (e.g., betamethasone) is given to promote fetal lung maturity.
      • MgSO₄ for Neuroprotection: Administered if GA is <32 weeks and delivery is anticipated, to reduce the risk of cerebral palsy.
      • Tocolysis: Generally not recommended, but may be considered for 48 hours to allow for steroid administration.
    • Pre-viable (<23-24 weeks):
      • Patient counseling is critical due to poor neonatal outcomes and significant maternal risks.
      • Options include expectant management or induction of labor.
  • Complications
    • Maternal:
      • Chorioamnionitis (intra-amniotic infection): Most common serious complication. Presents with fever, maternal/fetal tachycardia, uterine tenderness, and/or purulent vaginal discharge.
      • Placental abruption.
      • Postpartum endometritis.
    • Fetal/Neonatal:
      • Prematurity: The greatest risk, leading to respiratory distress syndrome (RDS), necrotizing enterocolitis (NEC), and intraventricular hemorrhage (IVH).
      • Infection/Sepsis.
      • Umbilical Cord Prolapse.
      • Pulmonary Hypoplasia: Can occur with prolonged, severe oligohydramnios from early PPROM.

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