Term prelabour rupture of membranes with GBS colonisation
Lucy is a 31-year-old G2P1 at 39+3 weeks. She felt a gush of clear fluid 6 hours ago and has had no contractions. Her previous delivery was spontaneous vaginal at term. She is group B streptococcus (GBS) positive on a rectovaginal swab at 36 weeks. She is afebrile, pulse 84, blood pressure 118/72; the uterus is soft and non-tender. The cardiotocograph is normal. Speculum examination confirms pooling of clear liquor; the cervix is 2 cm dilated, 50% effaced, and the head is at −1. She has no allergies and no history of caesarean section. She is keen for a natural birth and asks whether she can wait at home for labour to start. The unit has a midwife-led birthing centre and a consultant-led labour ward.
1. How would you manage her, and what are the risks of expectant management at term?
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At term with confirmed PROM, the main decision is induction of labour versus expectant management. She is GBS positive, which increases the risk of neonatal early-onset sepsis, and she has been ruptured for 6 hours. Offer induction of labour, ideally on the consultant-led labour ward, with continuous fetal monitoring and intrapartum GBS prophylaxis. Expectant management up to 24 hours is an option only if she is afebrile, the liquor is clear, the CTG is normal and she understands the risks. Those risks include chorioamnionitis, endometritis, neonatal infection, cord prolapse and placental abruption; the risk of infection rises with duration of rupture. She should not have digital vaginal examinations outside labour, and she should check her temperature and report any change in liquor, pain, bleeding or reduced fetal movements. Home waiting is not advisable with GBS colonisation and ruptured membranes. If she declines induction, document a clear safety plan and review her within 24 hours.
2. What antibiotic prophylaxis would you use, and when?
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For GBS prophylaxis in labour, give intravenous benzylpenicillin 3 g loading dose, then 1.5 g every 4 hours until delivery, or the local equivalent. If she has a severe penicillin allergy, use a cephalosporin or clindamycin according to sensitivities, or vancomycin if needed. Start prophylaxis when she is in established labour or when induction begins; if she remains undelivered with ruptured membranes beyond 18 hours, start prophylaxis according to local protocol. Prophylaxis is not treatment for chorioamnionitis. If she develops fever, uterine tenderness, purulent liquor or fetal tachycardia, take blood cultures and start broad-spectrum intravenous antibiotics, such as co-amoxiclav and gentamicin or local guidance, and expedite delivery. Inform the neonatal team so that the baby is assessed and monitored for sepsis. Document GBS status clearly in the notes and handover.
3. What if she develops a temperature of 38.2°C and a fetal heart rate of 170 bpm?
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This suggests chorioamnionitis with fetal tachycardia. Call for senior obstetric, anaesthetic and neonatal help. Start broad-spectrum IV antibiotics immediately after blood cultures, give paracetamol and fluids, and apply continuous CTG. Do not delay delivery for antibiotics. If the cervix is favourable and there is no contraindication, augment with oxytocin; if the CTG is non-reassuring or vaginal delivery is not imminent, proceed to caesarean section. Inform the anaesthetist about possible sepsis and the need for theatre. The neonatologist should attend delivery, and the baby may need cultures and antibiotics. After delivery, examine the placenta, send it for histology if indicated, and continue maternal antibiotics. Document the timeline and consider whether the infection was related to prolonged rupture of membranes or repeated examinations.