Spontaneous premature rupture of the membranes: bacteriology, histology and neonatal outcome

Abstract

Summary Spontaneous premature rupture of the membranes was associated with more than one-third of preterm deliveries in the John Radcliffe Hospital, Oxford, over an 8-month period. The prevalence of bacterial colonisation of the vagina, the placenta and the neonate and of inflammatory cell infiltration of the placenta and membranes was studied in 68 patients (39 delivered between 24 and 37 weeks and 29 after 37 weeks) and the findings were compared with those in 30 patients undergoing elective amniotomy at term. Bacterial colonisation of the neonates had occurred in 41 per cent in the preterm group compared with 28 and 23 per cent respectively in the two groups at term; inflammatory cell infiltration of the placenta was present in 33 per cent in the preterm group compared with 21 and 16 per cent in the term groups. There was poor correlation between bacterial colonisation of the vagina, placenta and neonate and chorioamnionitis. Although 7 of 42 babies in the preterm group died, only one death was associated with septicaemia. The major hazard to the neonate after spontaneous rupture of the membranes was preterm delivery, not infection. It is likely that both bacterial colonisation and inflammation of the placenta may be a consequence rather than a cause of spontaneous rupture of the membranes.