What is Premature Rupture of Membranes (PROM)?
Premature rupture of membranes (PROM), also called pre-labor rupture of membranes, is the rupture of the amniotic sac before labor begins at or after 37 weeks of gestation. 1, 2
Definition and Classification
PROM specifically refers to membrane rupture occurring at term (≥37 weeks) before the onset of labor contractions. 1, 2 This condition must be distinguished from preterm premature rupture of membranes (PPROM), which occurs before 37 weeks of gestation. 1, 2
Key Terminology
- PROM (Premature Rupture of Membranes): Rupture of fetal membranes after 37 weeks but before labor begins 2, 3
- PPROM (Preterm Premature Rupture of Membranes): Rupture of membranes before 37 weeks of gestation and before labor onset 1, 2
- Previable PPROM: Membrane rupture when the fetus cannot survive outside the uterus and is not a candidate for life-sustaining interventions 1
- Periviable PPROM: Membrane rupture during 20 0/7 to 25 6/7 weeks when the fetus may survive with life-sustaining interventions but faces high risk of death or severe morbidities 1
Clinical Significance and Epidemiology
PROM complicates approximately 8-10% of all pregnancies, while PPROM occurs in 2-3% of pregnancies. 2, 3, 4 PROM accounts for approximately one-third of all preterm deliveries. 2
Natural History
The majority of women with PROM will deliver within 7 days following membrane rupture. 1, 5 At term, PROM is associated with a relatively low rate of complications for both mother and fetus. 3 However, when PROM occurs preterm, it places both mother and fetus at significantly increased risk of short-term and long-term morbidity and mortality. 3
Associated Risks and Complications
Maternal Risks
- Infectious complications: Chorioamnionitis is the most frequent infectious complication, with risk increasing with duration of membrane rupture 5
- Maternal sepsis: Occurs in up to 6.8% of previable and periviable PPROM cases 6
- Hemorrhage and placental abruption: Higher risk with expectant management 6, 5
- Maternal mortality: Reported at a rate of 45 per 100,000 patients with previable PPROM 6
Neonatal Risks
- Prematurity-related complications: Including respiratory distress syndrome, bronchopulmonary dysplasia (up to 50% of surviving neonates), intraventricular hemorrhage, necrotizing enterocolitis, sepsis, and retinopathy of prematurity 7, 6
- Pulmonary hypoplasia: Results from insufficient amniotic fluid during critical fetal lung development 7, 6
- Skeletal deformities: Observed in 5-25% of cases 7
- Umbilical cord complications: Including cord prolapse and compression 2, 3
Prognostic Factors
Later gestational age at membrane rupture and higher residual amniotic fluid volume are the most consistently associated factors with improved perinatal survival. 6, 8
Gestational Age-Specific Survival Rates
- <16 weeks: No surviving neonates reported 6
- 16-19 6/7 weeks: Approximately 20% survival 6
- 20-21 6/7 weeks: Approximately 30% survival 6
- 22-23 6/7 weeks: Approximately 41% survival 6
Long-Term Outcomes
Children born after previable and periviable PPROM face significant long-term health challenges. Respiratory problems requiring treatment with respiratory medications occur in 50-57% of children at ages 2-5 years. 7, 6 At age 10, these children demonstrate worse lung function, mild pulmonary hypertension, and lower peak oxygen consumption compared to children delivered at similar gestational ages after PPROM at ≥28 weeks. 7