Prolonged Rupture of Membranes

Prolonged rupture of membranes is rupture of the membranes for 18 hours or more before birth, at any gestation. The longer the interval, the higher the chance that bacteria from the vagina ascend and infect the amniotic fluid, the placenta and the fetus. It matters because the risk of chorioamnionitis rises with each hour after rupture, and neonatal sepsis and maternal puerperal sepsis follow.

• Neonatal sepsis risk rises with the duration of rupture.
• Risk factors: group B streptococcus carriage, bacterial vaginosis, repeated vaginal examinations, prolonged labour, preterm rupture.
• Early antibiotics lower both maternal and neonatal infection.

Women report leakage of fluid for many hours or days, and may have fever, abdominal tenderness, foul-smelling discharge and maternal or fetal tachycardia. Some are well until infection sets in.

• Fever of 38 degrees Celsius or more.
• Uterine tenderness and offensive liquor.
• Differential diagnosis: urinary tract infection, malaria, appendicitis, endometritis, mastitis, viral illness.
• Complications: chorioamnionitis, neonatal sepsis, pneumonia, meningitis, maternal sepsis, postpartum endometritis, preterm birth, cord prolapse, abruption.

The approach is to confirm rupture and the time of onset, and to look for infection.

• Time of rupture from history; sterile speculum with pooling and nitrazine paper (pH above 6.5); placental alpha microglobulin 1 test where available.
• Temperature, pulse, blood pressure and uterine tenderness 4-hourly; fetal heart rate for tachycardia above 160 beats per minute.
• Full blood count (white cells above 15 x 10^9/L), C-reactive protein, urine culture, high vaginal and rectovaginal swabs, blood culture if febrile, malaria test.
• Ultrasound for amniotic fluid index and presentation; cardiotocography.

The principle is antibiotic cover from presentation and delivery without delay, with early treatment of infection.

• Supportive: admit; avoid digital vaginal examination; temperature 4-hourly; IV fluids (Ringer's lactate 1 litre over 4 hours) for fever; paracetamol; keep the neonatal team informed.
• Pharmacological: benzylpenicillin 5 million units IV then 2.5 million units 4-hourly until delivery (or ampicillin 2 g IV 6-hourly); chorioamnionitis: ampicillin 2 g IV 6-hourly plus gentamicin 5 mg/kg IV once daily until delivery then for 24 hours after fever settles, adding metronidazole 500 mg IV 8-hourly after caesarean section; paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours); misoprostol 25 micrograms vaginal 6-hourly (maximum 4 doses) or oxytocin starting at 2 mU/minute doubling every 30 minutes to a maximum of 32 mU/minute for induction; betamethasone 12 mg IM twice, 24 hours apart, only if delivery is before 34 weeks and 6 days and time allows; oxytocin 10 IU IM at birth.
• Procedures: induction or augmentation with delivery as soon as possible; caesarean section for obstetric reasons or fetal distress, without waiting for fever to settle.
• Special groups: penicillin allergy of low risk uses cefazolin 2 g IV then 1 g 8-hourly, and severe allergy uses clindamycin 900 mg IV 8-hourly plus gentamicin; newborns have a sepsis screen (full blood count, C-reactive protein, blood culture) and benzylpenicillin 50 mg/kg IV 12-hourly plus gentamicin 5 mg/kg IV 24-hourly for 48 hours pending culture, extended to 7 days if infection is confirmed.
• Red flags: temperature above 38 degrees Celsius, maternal pulse above 100 per minute, fetal heart rate above 160 beats per minute, foul liquor, hypotension, confusion.
• Follow-up: maternal temperature 4-hourly for 48 hours after birth; newborn observation for 48 hours; review at 6 weeks with a check for endometritis and wound infection.