Premature Rupture of Membranes (PROM)
24 TO 31 WEEKS
Delivery before 32 weeks’ gestation may lead to severe neonatal morbidity and mortality. In the absence of intra-amniotic infection, the physician should attempt to prolong the pregnancy until 34 weeks’ gestation. Physicians should advise patients and family members that, despite these efforts, many patients deliver within one week of preterm PROM. Contraindications to conservative therapy include chorioamnionitis, abruptio placentae, and nonreassuring fetal testing. Physicians should administer a course of corticosteroids and antibiotics and perform an assessment of fetal well-being by fetal monitoring or ultrasonography. After transport to a facility able to care for patients with preterm PROM before 32 weeks’ gestation, patients should receive daily (or continuous, if indicated) fetal monitoring for contractions and fetal well-being. Umbilical cord compression is common (32 to 76 percent)7 with preterm PROM before 32 weeks’ gestation; therefore, at least daily fetal monitoring is indicated. In addition, the physician should observe closely for fetal or maternal tachycardia, oral temperature exceeding 100.4°F (38°C), regular contractions, uterine tenderness, or leukocytosis, which are possible indicators of amnionitis. Corticosteroid administration may lead to an elevated leukocyte count if given within five to seven days of PROM.
Evidence suggests that prolonged latency may increase the risk of intra-amniotic infection. A retrospective analysis of 134 women with preterm PROM at 24 to
32 weeks’ gestation who received steroids and antibiotics found a nonsignificant trend toward intrauterine inflammation in patients with a latency period longer than one week. Delivery is necessary for patients with evidence of amnionitis. If the diagnosis of an intrauterine infection is suspected but not established, amniocentesis can be performed to check for a decreased glucose level or a positive Gram stain and differential count can be performed. For patients who reach 32 to 33 weeks’ gestation, amniocentesis for fetal lung maturity and delivery after documentation of pulmonary maturity, evidence of intra-amniotic infection, or at 34 weeks’ gestation should be considered.
BEFORE 24 WEEKS
The majority of patients will deliver within one week when preterm PROM occurs before 24 weeks’ gestation, with an average latency period of six days. Many infants who are delivered after previable rupture of the fetal membranes suffer from numerous long-term problems including chronic lung disease, developmental and neurologic abnormalities, hydrocephalus, and cerebral palsy. Previable rupture of membranes also can lead to Potter’s syndrome, which results in pressure deformities of the limbs and face and pulmonary hypoplasia. The incidence of this syndrome is related to the gestational age at which rupture occurs and to the level of oligohydramnios. Fifty percent of infants with rupture at 19 weeks’ gestation or earlier are affected by Potter’s syndrome, whereas 25 percent born at 22 weeks’ and 10 percent after 26 weeks’ gestation are affected. Patients should be counseled about the outcomes and benefits and risks of expectant management, which may not continue long enough to deliver a baby that will survive normally.
Physicians caring for patients with preterm PROM before viability may wish to obtain consultation with a perinatologist or neonatologist. Such patients, if they are stable, may benefit from transport to a tertiary facility. Home management of patients with preterm PROM is controversial. A study of patients with preterm PROM randomized to home versus hospital management revealed that only 18 percent of patients met criteria for safe home management. Bed rest at home before viability (i.e., approximately 24 weeks’ gestation) may be acceptable for patients without evidence of infection or active labor, although they must receive precise education about symptoms of infection and preterm labor, and physicians should consider consultation with experts familiar with home management of preterm PROM. Consider readmission to the hospital for these patients after 24 weeks’ gestation to allow for close fetal and maternal monitoring.
The prognosis in PROM varies. It depends in large part on the maturity of the fetus and the development of infection.
The only controllable factor associated with PROM is smoking. Cigarette smoking should always be discontinued during a pregnancy.
Davidson, Susan. Diseases Causes & Diagnosis Current Therapy Nursing Management Patient Education (Educational Publishing House. 1990)
Kumar. Robbins & Cotran Pathologic Basis of Disease (Elsevier Saunders Inc. 7th edition. 2005)
Huether. Understanding Pathophysiology (Mosby, Inc. 2nd edition. 2000)