Prelabour rupture of the membranes at or near term. Clinical and epidemiological studies

Abstract

Objectives: To study: (1) the risks and benefits for women with prelabourrupture of the membranes (PROM) after 34 weeks of gestation managed withdifferent expectant periods from 24 to 72 hours; (2) perinatal infectiousmorbidity in the different groups and the association between demographic,intrapartum and postpartum variables and neonatal sepsis; (3) theinfluence of bath on infectious morbidity in mothers and neonates in womenwith PROM; (4) the false negative rate using a sterile speculum examination for thediagnosis of rupture of the membranes (ROM) compared to Diamine oxidase(DAO); (5) possible risks for the mother and the baby when the women wereallowed to return home without further controls if amniotic fluid was notvisible at the speculum examination; (6) the prevalence and risk factorsfor PROM in an urban Swedish population.Material and methods: Studies I-III were based on a randomised studycomparing two different regimens in women with PROM. Women withoutcontractions within two hours (n=1012) were randomised to induction thefollowing morning after PROM ("early induction group") or induction twodays later ("late induction group"). Digital examination of the cervix wasavoided until onset of active labour. Labour was induced with oxytocin ifno spontaneous contractions occurred or if chorioamnionitis or fetaldistress was detected.Study IV was based on women admitted for suspected rupture of themembranes after 34 weeks of gestation in which no amniotic fluid wasvisible at the sterile speculum examination. A test for DAO was performed.No further controls were performed if amniotic fluid was not visible atthe speculum examination. Neonatal and obstetric outcome was recordedprospectively. Study V was based on a sample of 2880 women randomlyselected from the national population register. They had delivered 2270times at hospitals in the Göteborg area and 2242 of these case recordswere found. The case records were systematically analysed for theoccurrence of PROM and potential risk factors for PROM. Two thousand twohundred and eight of these deliveries occurred after 34 weeks ofgestation. The analyses were based on these 2208 deliveries.Results: There were no differences in the frequency of neonatal ormaternal infections if the mother were randomised to early or lateinduction. No differences were found in the frequency of caesareansections between the randomised groups. In nulliparous women ventouseextraction was more often used in the "early induction group" compared tothe "late induction group", 14% and 7% respectively (p<0.05). There was nodifference in the incidence of neonatal infections between the groups.Clinical neonatal sepsis was associated with time from PROM to deliveryover 32 hours, caesarean section, parous women and gestational age between34 and 36 weeks. The false negative rate of a speculum examination of thediagnosis of rupture of the membranes in women without amniotic fluidvisible at a speculum examination was 12%. This study did not show anyfalse negative speculum examination. The prevalence of PROM after 34 weeksstepwise regression analysis risk factors for PROM were age at delivery"35 years, primiparity, premature contractions, PROM in a previouspregnancy and bleeding in the first trimester.