Premature rupture of membranes

Diagnosis - Water Break Whodunit

• Initial Steps:
  • Sterile Speculum Exam: Visualize for pooling of fluid.
  • Nitrazine Test: Amniotic fluid is alkaline (pH > 6.5), turning paper blue. ⚠️ False positives: blood, semen, BV.
  • Fern Test: Fluid air-dries on a slide, showing a crystallization pattern (arborization). Most specific office test.
• If Diagnosis Unclear:
  • Ultrasound: Assess for oligohydramnios (AFI < 5 cm).

⭐ The fern test is highly specific for amniotic fluid, as the characteristic arborization pattern is caused by the crystallization of amniotic salts and proteins when dried.

Etiology & Risks - The Weak Link

• Infection: The primary driver, weakening membranes.
  • Ascending genital tract infections (e.g., bacterial vaginosis)
  • UTIs, chorioamnionitis
• Uterine Overdistension / Stress:
  • Polyhydramnios, multiple gestation
• Iatrogenic/Traumatic:
  • Amniocentesis, cervical surgery (LEEP, conization)
• Intrinsic Membrane Weakness:
  • Prior PPROM, smoking, nutritional deficiencies (Vit C, copper)

⭐ A history of PPROM in a prior pregnancy is the single strongest predictor for recurrence.

Complications - Danger Zone Delivery

• Maternal Risks:
  • Chorioamnionitis: Most common; intra-amniotic infection.
  • Placental abruption: Can cause severe hemorrhage.
  • Endometritis & retained placenta post-delivery.
• Fetal/Neonatal Risks:
  • Umbilical Cord Prolapse: EMERGENCY requiring immediate C-section.
  • Pulmonary Hypoplasia: High risk if rupture <24 weeks.
  • Prematurity: Major cause of RDS, IVH, NEC.
  • Infection: Neonatal sepsis, pneumonia.

⭐ Chorioamnionitis is the most frequent major complication. Suspect with maternal fever, uterine tenderness, maternal or fetal tachycardia, and purulent amniotic fluid.

Management - The Ticking Clock

Management hinges on gestational age and presence of infection or fetal distress.

• Expectant Management (<34 wks):
  • Corticosteroids (e.g., Betamethasone): For fetal lung maturity.
  • Latency Antibiotics (e.g., Ampicillin + Azithromycin): To prolong pregnancy.
  • Magnesium Sulfate: If <32 wks for fetal neuroprotection.

⭐ In PPROM, latency antibiotics are given to prolong the interval to delivery and reduce neonatal infectious morbidity, not primarily to treat maternal infection.

High-Yield Points - ⚡ Biggest Takeaways

• Rupture of membranes before labor onset is the defining feature.
• Diagnose with a sterile speculum exam showing amniotic fluid pooling, a positive nitrazine test (turns blue), and microscopic ferning.
• The greatest risks are intra-amniotic infection (chorioamnionitis) and preterm labor.
• At term (≥37 weeks), proceed to delivery and induce labor.
• For PPROM <34 weeks, manage expectantly with latency antibiotics (e.g., ampicillin, azithromycin) and corticosteroids for fetal lung maturity.