Synonyms and related keywords: spontaneous rupture of membranes in the premature patient, preterm premature rupture of membranes, prolonged rupture of membranes, PROM, PPROM, prolonged PPROM, SROM, SPROM, ROM, intraamniotic infection, pulmonary hypoplasia, oligohydramnios

INTRODUCTION

Eighty-five percent of neonatal morbidity and mortality is a result of prematurity. Preterm premature rupture of the membranes (PPROM) is associated with 30-40% of preterm deliveries and is the leading identifiable cause of preterm delivery. The 3 most common risk factors for PPROM are smoking, previous preterm delivery, and vaginal bleeding at any time during the index pregnancy.

The terminology pertaining to premature rupture of membranes (PROM) can be confusing, so understanding the subtle distinctions can be valuable. PROM is rupture of the membranes (ROM) prior to the onset of labor. PROM is used appropriately when referring to a patient who is beyond 37 weeks of gestation, has presented with spontaneous rupture of the membranes (SROM), and is not in labor. PPROM is ROM prior to the onset of labor in a patient who is at less than 37 weeks of gestation. PROM is ROM prior to 37 weeks of gestation and may imply that the patient is in labor. This has also been abbreviated as SPROM, ie, spontaneous premature rupture of membranes. Otherwise, this patient is referred to as having PPROM. Prolonged ROM is any ROM that persists for more than 24 hours. This article focuses on the management of PROM (at term) and PPROM.

PROM AT TERM

PROM is ROM prior to the onset of labor at or beyond 37 weeks of gestation. Incidence of PROM is approximately 10% of pregnancies. Patients with PROM may present with chief complaints of leaking fluid, vaginal discharge, vaginal bleeding, and pelvic pressure, but they are not in labor. (Labor is defined as regular, painful uterine contractions resulting in progressive cervical effacement or dilation.)

The diagnosis of PROM can be made by looking for pooling of fluid in the vagina or leakage of clear fluid from the cervix and by ferning or arborization of this vaginal fluid when allowed to dry on a glass slide and viewed with a light microscope and/or contacted with Nitrazine paper (which turns blue in contact with the vaginal fluid). Blood contamination of the Nitrazine paper can invalidate results.

Avoid a digital cervical examination unless prompt or immediate delivery is expected. If the diagnosis is still in question, the amniotic fluid index (AFI) can be helpful. If doubt still exists, transabdominal instillation of 1 mL of indigo carmine dye in 9 mL of sterile saline into the amniotic cavity under ultrasound guidance and observations of staining on a vaginal tampon or a sanitary pad should alleviate any question of ROM.

The natural history of PROM progresses in such a way that 90% of patients enter spontaneous labor within 24 hours. The major question regarding management of these patients is whether to allow them to enter labor spontaneously or to induce labor. In large part, the management of these patients depends on their desires; however, the major maternal risk at this gestational age is intrauterine infection. The risk of intrauterine infection increases with the duration of ROM. Evidence supports the idea that induction of labor, as opposed to expectant management, decreases the risk of chorioamnionitis without increasing the cesarean delivery rate.

Hannah et al studied 5041 women with PROM who were randomly assigned to induction of labor with intravenous oxytocin or vaginal prostaglandin E2 gel versus expectant management for as many as 4 days with induction of labor for complications. The researchers concluded that, in women with PROM, induction of labor with oxytocin or prostaglandin E2 gel and expectant management resulted in similar rates of cesarean delivery and neonatal infection. Induction with oxytocin, however, resulted in a lower risk of maternal infection (endometritis) when compared with expectant management. Additionally, the women in the study viewed induction of labor more favorably than expectant management.

A small study in the European literature concluded that women with PROM at term who have an unfavorable cervical examination can be safely managed expectantly and that expectant management resulted in fewer operative vaginal deliveries. This prospective randomized trial enrolled a total of 154 patients (Alcalay et al, 1996). In addition, several prospective studies have reported that with an unfavorable cervix, expectant management decreased the cesarean delivery rate and length of labor without increasing infectious morbidity.

If a patient desires expectant management after being presented with the evidence and a recommendation by her caregiver, undertake this course in the hospital and not at home. In Hannah's subanalysis of the International Term PROM Study, 650 women were expectantly managed at home and 1017 were expectantly managed in the hospital. The conclusions of this analysis were that, "expectant management at home, rather than in a hospital, might increase the likelihood of some adverse outcomes (eg, cesarean section rate, numbers of neonates admitted to the NICU for >24 hours, neonatal sepsis)." An additional consideration in hospital management is the choice of care to administer in the hospital. The safest course is complete bedrest with continuous fetal heart rate monitoring. Alternative management strategies include intermittent monitoring with some ambulation, which includes bathroom privileges.

Regardless of which management scheme is undertaken, always consider a patient's desires when designing a plan for management, and then carefully document the discussion points.

PPROM

PPROM is far more complicated than PROM at term. Questions about hospital versus home management, steroid administration, antibiotic prophylaxis, tocolytic use, risks for pulmonary hypoplasia, fetal surveillance, bed rest, and hydration may depend on gestational age and multiple comorbidities. Important factors affecting neonatal outcome are gestational age at delivery, estimated fetal weight, presence or absence of infection, and whether a course of steroids has been completed. These concerns are addressed throughout the remainder of this article.

Multiple options for management are available in the absence of fetal distress, nonreassuring fetal heart rate tracings, overt intrauterine infection, or a maternal indication for delivery.

MANAGEMENT OF PPROM

The gestational age and the presence or absence of an intraamniotic infection (chorioamnionitis) determine the initial management of patients with PPROM. If a patient has evidence of intraamniotic infection by clinical examination (eg, maternal temperature > 38°C, fetal tachycardia, fundal tenderness, foul or purulent vaginal discharge, maternal tachycardia, elevated C-reactive protein level) or by amniocentesis (positive Gram stain finding, glucose <20 mg/dL, positive amniotic fluid culture results for aerobic or anaerobic organisms or Mycoplasma species), institution of broad-spectrum antibiotics and delivery are necessary, regardless of gestational age.

Reduced fetal heart rate variability is not a sensitive sign in preterm infants. If a patient is at more than 32 weeks of gestation and has documented fetal lung maturity, delivery is recommended. Finally, if a patient has reached 32-35 weeks’ gestation and has documented ROM, delivery in the absence of documented pulmonary maturity may be considered in institutions with a NICU equipped to manage the complications of prematurity.

Each institution must have an idea of how well neonates at various gestation ages do at that particular institution. No uniform agreement has been reached on the optimal gestational age (regardless of local NICU statistics) at which delivery should be undertaken. The overall goal is to manage the patient expectantly until she has reached a gestational age beyond which neonatal morbidity and mortality is minimal and to achieve delivery before the mother and/or her fetus become infected.

PPROM & ANTIBIOTICS, CORTICOSTEROIDS, FETAL SURVEILLANCE, AND TOCOLYTICS

If the decision to manage a patient expectantly has been made, the institution of broad-spectrum antibiotics is advantageous. Multiple trials have examined the advantages and disadvantages of using antibiotics and the choice of antibiotics. Use of antibiotics has been associated with prolongation of pregnancy and reduction in infant and maternal morbidity.

The summary of the available literature supports the use of ampicillin (2 g IV q6h) and erythromycin (250 mg IV q6h) for 48 hours, followed by amoxicillin (250 mg PO q8h) and erythromycin base (333 mg PO q8h) for 5 days, for a total of 7 days of antibiotics. An alternative is ampicillin/sulbactam (3 g IV q6h) for 48 hours, followed by amoxicillin/clavulanate (250 mg PO q8h) for 5 days, for a total of 7 days of antibiotics. A broad-spectrum cephalosporin or clindamycin may be substituted in patients who are allergic to penicillin. Prolonged antibiotics offer no advantages and may promote the emergence of resistance (eg, ampicillin-resistant Escherichia coli).

Little controversy about who should receive steroids should exist. The Consensus Development Panel of the National Institutes of Health recommends corticosteroid use for women with PPROM prior to 30-32 weeks of gestation in the absence of clinical chorioamnionitis. The dose is betamethasone 12 mg IM qd for 2 days. In the initial statement, an allowance was also made for dexamethasone, but a considerable amount of evidence has developed since then that favors betamethasone for many reasons. No evidence supports the use of subsequent courses of this therapy.

Perform antepartum fetal surveillance at least daily, which may consist of a nonstress test (NST) and AFI. No evidence supports one form of testing over another or any specific frequency.

Tocolytics may be used to prolong gestation long enough to complete a course of corticosteroids (betamethasone 12 mg IM qd for 2 d). Be absolutely certain that an intraamniotic infection is not present before beginning tocolytics.

Pelvic rest is of utmost importance, as the risk of ascending infection increases not only with the duration of ruptured membranes but also with manipulation of the cervix. Examine the cervix with a sterile speculum and not digitally. Furthermore, there is no need for frequent cervical examinations in a patient who is without complaints of regular uterine contractions, pelvic pressure, vaginal bleeding, or other signs and/or symptoms of labor.

The single exception is in the patient who has advanced cervical dilation and/or a nonvertex presentation. These patients are at increased risk for umbilical cord prolapse and may require more frequent cervical examinations (sterile speculum) to assess whether further cervical dilation has occurred. If the patient has advanced cervical dilation (ie, enough dilation to allow an umbilical cord to prolapse) and/or a nonvertex presentation, continuous fetal heart rate monitoring may be necessary. In many instances of cord prolapse, the only sign may be severe variable decelerations or a prolonged deceleration in the fetal heart rate. This is difficult to diagnose with intermittent fetal heart rate monitoring.

Again, any evidence of intraamniotic infection should prompt a move toward delivery. Practitioners should have a low threshold for diagnosing infection in light of recent evidence documenting how much more poorly neonates who are infected do compared to neonates who are not infected.

PPROM IN THE SECOND TRIMESTER

ROM prior to fetal viability poses unique problems. From 1984-1995, 11 maternal and fetal outcomes in pregnancies with PPROM in the second trimester (13-26 wk) were reported. The major maternal risk is infection, namely chorioamnionitis. The major morbidity in the fetus with midtrimester ROM is lethal pulmonary hypoplasia from prolonged, severe, early oligohydramnios.

Chorioamnionitis occurs in 30-60% of patients with second-trimester PPROM. The risk of infection increases with duration of ROM and an AFI less than 2.0 cm. Frequent examinations are necessary to ensure maternal safety. Patients must be educated about the warning signs of intraamniotic infection, and they must take their temperature 3 times a day at home. These patients do not require hospitalization if no evidence of vaginal bleeding or infection exists. Patients may consider admission for inpatient management at 24 weeks, the juncture currently considered the point of viability at most institutions.

Pulmonary hypoplasia is the most serious fetal complication and can be lethal. The presence of severe (AFI <2.0 cm), prolonged (>14 d), and early (<25 wk at onset) oligohydramnios has been associated with a neonatal mortality rate greater than 90% in one study. In other studies, the gestational age at the time of PPROM had the most significance when predicting pulmonary hypoplasia. In the human fetus, ROM during the canalicular stage (13-25 wk) has the most dismal prognosis. The diagnosis of pulmonary hypoplasia is made at autopsy by weighing the lungs. Several schemes exist for predicting pulmonary hypoplasia antenatally using lung lengths and/or thoracic circumference ratios, but the functional capacity of the lung cannot be predicted, only the amount of tissue present.

Midtrimester (13-26 wk) PPROM has a dismal prognosis. Survival varies with gestational age at diagnosis (from 12% when diagnosed at 16-19 wk to as much as 60% when diagnosed at 25-26 wk). Until viability, maternal well-being should be of paramount concern.

SUMMARY

Manage PROM at term according to the patient's wishes, the cervical examination, and the presence or absence of any comorbidities (eg, infection). Evidence to support induction of labor shortly after diagnosis of PROM exists, and this is the protocol at the author’s institution, with few exceptions.

PPROM is considerably more complicated and requires a thorough evaluation for gestational age, fetal position, presence of infection, and fetal and maternal well-being. Decisions about management are affected by each of these variables.

Second-trimester PPROM has a dismal prognosis. This condition requires an understanding of the literature, thorough counseling, and documentation.

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