Description of the condition
Preterm prelabour rupture of membranes (PPROM) is the spontaneous rupture of the membranes before 37 weeks’ gestation, and where there is at least an hour between membrane rupture and the onset of contractions. It is further classified by gestational age: mid-trimester PPROM (before 24 weeks), early PPROM (24 to 34 weeks), and near-term PPROM (34 to 37 weeks). It occurs in 3% of pregnancies and is responsible for approximately one-third of all preterm births (Bartfield 1998; Goldenberg 1998).
A number of factors increase the risk of PPROM, including history of premature birth, black race, genetic factors, socio-economic status, smoking, low maternal weight, multiple pregnancy, nutritional deficiencies, prior cervical conisation, cervical cerclage, amniocentesis, vaginal bleeding in pregnancy and infection (Mercer 2007). At the same time, PPROM often occurs in the absence of any known risk factors (Besinger 1993; Medina 2006; Mercer 2007; Mingione 2006). The physiological mechanisms leading to PPROM are poorly understood, but may include excessive stretching of the membranes (due to uterine over-distension, as in multiple pregnancies, or an increase in the amount of fluid around the fetus, i.e. polyhydramnios); membrane defects like decreasing collagen content; placental abruption, or problems arising from infection. Between one-quarter and one-half of women with PPROM will have infection at the time of presentation (Simhan 2005).
PPROM may result in immediate risks such as cord prolapse, cord compression and placental abruption; and later problems such as maternal or neonatal infection, as well as the use of interventions including induction of labour, caesarean section and instrumental vaginal delivery. It is estimated that one-half of women with PPROM will go into labour within a week, and three-quarters within a fortnight (Goldenberg 2008). Premature delivery is the major cause of perinatal morbidity and mortality associated with PPROM, and survival of the baby after PPROM largely depends on gestational age (Mercer 2003). The related morbidities associated with prematurity include respiratory distress syndrome (RDS), intraventricular haemorrhage, necrotising enterocolitis, prolonged stay in the neonatal nursery, difficulty with thermoregulation, difficulty with breastfeeding and infection. Current evidence suggests that fetal complications are directly related to gestational age at delivery. Several investigators observed a decrease in neonatal morbidity associated with birth after 34 weeks’ gestation (Lewis 1996b; Mercer 2003; Neerhof 1999). The incidence of RDS, hyperbilirubinaemia and duration of stay in the neonatal nursery was significantly reduced in infants born after 34 weeks’ gestation, compared with those born earlier (Lewis 1996b; Neerhof 1999). On the other hand, prolonged rupture of membranes with lack of amniotic fluid around the fetus may have an impact on limb movements, causing postural deformities and on lung development, predisposing to pulmonary hypoplasia and severe respiratory distress after delivery. Mothers are at increased risk of placental abruption and antenatal as well as postpartum infection. Serious maternal consequences following PPROM are uncommon, but serious infections occur in approximately 5% of babies. Maternal infection during pregnancy, chorioamnionitis, may lead to serious complications in newborns, including cerebral palsy and septicaemia (Neufeld 2005; Ronnestad 2005; Woldesenbet 2005). Most of the evidence on the consequences of PPROM has come from studies in developed countries; outcomes for babies following PPROM, particularly at low gestational ages, may be very poor in developing countries, and mothers may also face risks of serious infectious morbidity (Obi 2007).
While preterm labour and PPROM are distinct, many of the interventions used to treat the conditions are the same. Management of PPROM varies in different settings and according to facilities, local guidelines and protocols and the approach of individual clinicians (ACOG Committee 2007; Buchanan 2004; Giles 2005; Lumley 1991). In a survey of obstetric units in the United States of America, 30% of the units surveyed had formal management protocols (Ramsey 2004). The management of PPROM is dependent upon the gestational age at which rupture of the membranes occurs. The health benefits for the fetus in continuing a pregnancy after PPROM may be considerable, particularly in the late second and early third trimesters of pregnancy (between 24 and 34 weeks’ gestation). Current evidence suggests that among women with PPROM between 24 and 34 weeks' gestation, the use of antibiotics significantly improves short-term neonatal and maternal morbidity including prolongation of pregnancy, reduced need for surfactant and oxygen therapy, reduction in neonatal infection, and less risk of abnormal cerebral ultrasound, At the same time particular antibiotics may be associated with increased risk of neonatal morbidity, and long term follow-up showed no clear differences between children whose mothers had or had not been treated with antibiotics (Kenyon 2010; Kenyon 2007). Antenatal corticosteroids have been shown to reduce the risk of neonatal respiratory distress, and serious morbidity in the preterm neonate although again, the long term effects are less clear (Crowther 2011; Roberts 2006).
There remains no consensus as to the optimal management of PPROM in women in whom the fetus is relatively mature, at gestations near to term (greater than 34 weeks' gestation). A Cochrane review concluded that there was too little evidence on the benefits and harms of early delivery compared with expectant management (Buchanan 2010). The aim of planned expectant management is to maximise the benefits of further fetal maturity while avoiding the potential harms of remaining in utero. It involves observation of the mother and fetus for early signs of fetal or maternal infection while awaiting the spontaneous onset of labour and, if labour does not ensue, planning for delivery at term. There is no evidence to support the best place to carry out this observation. Although clinicians may feel that it is easier to monitor women in a hospital setting, women’s views may be different. Ramsey 2004 et al noted that, in a study of obstetric services in the United States, 43% of respondents would consider outpatient care of women after PPROM where the fetus was of viable gestational age, despite the lack of evidence on this approach.
There are a number of possible interventions for PPROM including the use of steroids (Roberts 2006); antibiotics (Kenyon 2010); amnioinfusion (Hofmeyr 1998); tocolytics (Seibel-Seamon 2008); and planned early birth versus expectant management (Buchanan 2010) which are the subject of other Cochrane reviews, and are outside the scope of this review.
Description of the intervention
For women with mid-trimester PPROM, before fetal viability has been established, discharge home has been one of the traditional mainstays of management. Where the fetus is viable, discharge home (as opposed to hospital care) has been more controversial. The advantages of home management may include convenience to women and their families, and reduced costs for healthcare providers. Set against this are the disadvantages associated with any increased risk which may arise from distance from facilities for delivery or emergency care.
In some circumstances, outpatient care after PPROM may not be suitable: for example, where either the mother or the fetus required continuous monitoring or where treatment is required that it would not be feasible to provide at home. Hospital care has also been used to enforce bed rest, which, in the past has formed part of management of PPROM, although there is no evidence that bed rest is helpful, and no evidence that women at home, advised to rest, are less likely to comply.
Some conditions preclude the use of outpatient care including symptomatic infection, fetal compromise or the onset of labour (Ellestad 2008; Lewis 1996). There is, however, concern that, irrespective of the condition of the mother or baby following PPROM, outpatient management could place women at serious risk of infection or fetal distress that requires rapid intervention.
Women considered suitable for possible home management following PPROM include those living within easy travelling distance of hospital and with access to reliable transportation. Planned home management can be initiated after a period of monitoring in hospital and, when appropriate, treatment with antibiotics has commenced. Ideally women should not be in labour and there would be no evidence of infection or oligohydramnios (Ayres 2002; Bartfield 1998). It is not clear what proportion of women with PPROM would meet these criteria.
Why it is important to do this review
Women with PPROM have been predominantly managed in hospital. It is possible that selected women could be discharged home after a period of observation. The safety of home management has not been established, neither is it known whether women prefer this approach, nor whether it would offer potential for reduced costs for health service providers.