Membrane Rupture Without Labour

Membrane rupture without labour is rupture of the amniotic sac with no regular contractions or cervical change, at any gestation, so the woman is in a latent period before labour. Most women labour within 24 hours at term, while at earlier gestations the latent period can extend to days or weeks. It matters because management depends on gestation, with infection the main risk during waiting and prematurity the main risk of delivery.

• Preterm rupture without labour is a common reason for admission before term.
• Risk factors: previous preterm rupture, smoking, genital infection, polyhydramnios, multiple pregnancy, short cervix.
• Each gestation band has a fixed plan, and infection overrides it.

Women have leakage of fluid, a damp pad or sudden gush, with no pain or only mild cramps. The uterus is soft and the cervix is closed or minimally open on speculum examination.

• Fluid pools in the posterior fornix.
• Fever and foul liquor point to infection.
• Differential diagnosis: urinary incontinence, vaginal discharge, mucus plug loss, bacterial vaginosis, cervicitis.
• Complications: chorioamnionitis, labour, cord prolapse, abruption, pulmonary hypoplasia (before 24 weeks), neonatal sepsis, prematurity, stillbirth.

The approach is to confirm rupture and gestation and to look for infection and fetal compromise.

• Sterile speculum: pooling of fluid, nitrazine paper blue (pH above 6.5), ferning; placental alpha microglobulin 1 or insulin-like growth factor binding protein 1 test where available.
• Ultrasound for gestation, amniotic fluid index, presentation, fetal weight and cord position; cardiotocography after 24 weeks.
• Temperature, pulse, full blood count, C-reactive protein, high vaginal and rectovaginal swab, urine culture.
• No digital examination unless in labour.

The principle is a gestation-based plan with antibiotics, steroids and magnesium, and delivery for infection, abruption or fetal compromise.

• Supportive: admit; pelvic rest; temperature 4-hourly; pad checks; fetal movement counts; corticosteroid and neonatal planning; transfer to a unit with neonatal intensive care if below 34 weeks.
• Pharmacological: before 37 weeks give amoxicillin 500 mg oral 8-hourly plus erythromycin 250 mg oral 6-hourly for 7 days (azithromycin 1 g oral once if erythromycin is unavailable); betamethasone 12 mg IM twice, 24 hours apart, between 24 and 34 weeks and 6 days; magnesium sulphate 4 g IV over 20 minutes then 1 g per hour until delivery for 24 hours at most before 32 weeks; nifedipine 20 mg oral once then 10 to 20 mg every 6 to 8 hours for up to 48 hours for contractions in a woman without infection; at term give benzylpenicillin 5 million units IV then 2.5 million units 4-hourly in labour for group B streptococcus carriage or rupture of 18 hours or more; chorioamnionitis: ampicillin 2 g IV 6-hourly plus gentamicin 5 mg/kg IV once daily.
• Procedures: at 37 weeks or later induce within 24 hours using 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; at 34 to 36 weeks and 6 days offer induction or expectant care to 37 weeks with close surveillance; before 34 weeks expectant care with surveillance to 34 weeks and delivery then; delivery at once for infection, abruption, cord prolapse or abnormal cardiotocography.
• Special groups: RhD negative women give anti-D immunoglobulin 500 IU IM within 72 hours of any bleeding; previous caesarean section avoids misoprostol and uses oxytocin or a Foley catheter with a 30 mL balloon; HIV positive women continue tenofovir 300 mg, lamivudine 300 mg and dolutegravir 50 mg oral once daily.
• Red flags: temperature above 38 degrees Celsius, maternal pulse above 100 per minute, fetal heart rate above 160 beats per minute, foul liquor, bleeding, contractions, palpable cord.
• Follow-up: full blood count and C-reactive protein every 2 to 3 days in hospital; amniotic fluid index weekly; growth scan every 2 weeks; newborn sepsis surveillance; review at 6 weeks.