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This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.
The Bottom Line
- PROM = membrane rupture before labor; PPROM = PROM before 37 weeks
- Diagnosis: sterile speculum exam showing pooling, nitrazine positive alkaline fluid, or ferning
- Avoid digital exams unless delivery is imminent
- Term PROM: induction is generally recommended
- PPROM <34 weeks without infection/fetal compromise: steroids, latency antibiotics, expectant management, and GBS prophylaxis as indicated
Overview
PROM is rupture of amniotic membranes before labor. PPROM occurs before 37 weeks. Major risks are ascending infection, cord prolapse, abruption, and prematurity. Management depends on gestational age and infection/fetal status.
Epidemiology
Term PROM is common and often followed by labor. PPROM contributes substantially to preterm birth. Risk factors include prior PPROM, infection, smoking, bleeding, short cervix, uterine overdistension, and invasive procedures.
Clinical Features
Symptoms
Sudden gush or persistent leakage of clear fluid
Ongoing wetness requiring pads
Contractions or pelvic pressure
Fever, chills, uterine pain, or foul fluid
Decreased fetal movement or cord prolapse symptoms
Signs
Pooling in posterior fornix
Fluid from cervical os with cough/fundal pressure
Maternal fever, uterine tenderness, fetal tachycardia, purulent fluid
Umbilical cord visible/palpable = cord prolapse
Nonreassuring fetal tracing
Investigations
First-line
Sterile speculum examinationLook for pooling, fluid from os, cervicitis, bleeding, and cord prolapse
Nitrazine and ferningNitrazine false positives with blood, semen, infection; ferning reflects amniotic fluid crystallization
UltrasoundAmniotic fluid volume, presentation, gestational age, growth, placental location
Second-line
Commercial amniotic fluid testsPAMG-1 or IGFBP-1 tests when traditional tests equivocal
GBS cultureObtain if status unknown and gestational age appropriate
Infection assessmentMaternal temperature, WBC trend, fetal HR, uterine tenderness, fluid odor
Specialist
MFM consultationEarly PPROM, periviable gestation, anomaly, infection concern
Neonatology consultationPPROM remote from term or anticipated preterm delivery
1
Term PROM
- Induction of labor generally recommended, commonly with oxytocin
- GBS prophylaxis if positive, unknown with risk factors, or otherwise indicated
- Short expectant management may be considered in selected patients
2
PPROM 34-36 weeks
- Delivery versus expectant management individualized
- Give GBS prophylaxis if indicated
- Evaluate for infection, abruption, labor, and fetal status
3
PPROM 24-33 weeks
- Expectant inpatient management if no infection, abruption, cord prolapse, labor, or fetal compromise
- Antenatal corticosteroids
- Latency antibiotics
- Magnesium sulfate if early preterm delivery imminent
- GBS prophylaxis when delivery occurs if indicated
4
Immediate delivery indications
- Chorioamnionitis, nonreassuring fetal status, abruption, cord prolapse, or advanced labor
- Broad-spectrum antibiotics and delivery for intraamniotic infection
Complications
- Chorioamnionitis: Fever, uterine tenderness, foul fluid, fetal tachycardia
- Neonatal sepsis: Risk rises with prolonged rupture and GBS
- Cord prolapse: Emergency with malpresentation/high presenting part
- Placental abruption: PPROM increases risk
- Pulmonary hypoplasia: Severe early oligohydramnios can impair lung development
USMLE Step 2 CK Exam Tips
- 1PROM diagnosis: pooling, nitrazine, ferning
- 2Avoid digital cervical exam after ROM unless delivery imminent
- 3Term PROM = induce labor
- 4PPROM before 34 weeks and stable = steroids + latency antibiotics + expectant management
- 5Fever + uterine tenderness + fetal tachycardia after ROM = chorioamnionitis → antibiotics and delivery
- 6Nitrazine false positives: blood, semen, bacterial vaginosis
- 7Cord prolapse after ROM = elevate presenting part and emergency cesarean unless vaginal delivery imminent
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