(1)
Department of Family Medicine, University of California, Riverside, Riverside, CA, USA
Key Points
1.
Premature rupture of membranes (PROM) is defined as rupture prior to the onset of labor.
2.
Preterm premature rupture of membranes (PPROM) is defined as PROM occurring prior to 37 weeks’ gestation.
3.
Rupture of membranes is followed by onset of labor within 24 h in 90 % of term patients and 50 % of preterm patients.
4.
PROM is associated with an increased risk of ascending infection. This risk increases with duration of rupture.
Background
For most women, the pattern of labor is predictable. In general, women first note the onset of contractions that are relatively mild and irregular. As labor progresses, the contractions become stronger and more regular and of increased duration. Spontaneous rupture of membranes generally follows the development of a regular contraction pattern as cervical dilation progresses. In approximately 10 % of cases, however, spontaneous rupture of membranes occurs prior to the onset of labor. This is defined as premature rupture of membranes (PROM).
Premature, in this case, does not refer to gestational age but to labor. If rupture of membranes precedes labor and is prior to 37 weeks’ gestation, the condition is referred to as preterm premature rupture of membranes (PPROM). Rupture of membranes is generally followed by onset of labor within 24 h. Ninety percent of patients at term and 50 % of preterm patients will begin labor within 24 h of spontaneous rupture of membranes. For term patients, PROM will generally mark impending labor and management can be expectant. PPROM often marks the onset of preterm labor and patients should be managed appropriately for their degree of prematurity. PPROM complicates approximately 30 % of all preterm deliveries and is associated with significant morbidity and mortality. The most significant complication of PPROM is infection.
A number of factors have been associated with PROM including infectious, anatomic, and pregnancy-related factors (see Table 8.1). A considerable number of cases, however, are idiopathic. Trichomonas, bacterial vaginosis, urinary tract infection (UTI), gonorrhea, chlamydia, and group B strep are among the infectious agents known or suspected to be associated with PROM. Women with documented cervical incompetence are also at increased risk for PROM. Amniocentesis is associated with an increased risk of PROM. This risk may be, in part, related to the experience of the provider performing the procedure. For this reason, patients requiring amniocentesis should be referred to providers with considerable experience. Placental abruption is occasionally associated with PROM and should be considered in the evaluation of patients with PROM.
Table 8.1
Risk factors for PROM
Infection |
Hydramnios |
Incompetent cervix |
Placental abruption |
Amniocentesis |
Diagnosis
History
Patients with PROM will often report discharge or “leaking” per vagina. This fluid leak may be subtle (e.g., increased wetness noted on undergarments or pants) or may be substantial (e.g., a “gush” of fluid). A careful history should be obtained to distinguish the causes of discharge such as cervical infection, physiological mucus production (or loss of the mucus plug), urinary incontinence, or UTI. Although each of these requires evaluation and diagnosis, management varies considerably from that for PROM.
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