Recurrent Preterm Membrane Rupture

Recurrent preterm membrane rupture is rupture of the membranes before 37 weeks in a woman who had preterm rupture in an earlier pregnancy. The recurrence risk is several times the baseline. Causes include persistent genital infection, cervical shortening, smoking and abnormal membrane or collagen strength. It matters because earlier gestation at the first rupture predicts earlier rupture again, and cervical surveillance and progesterone can lower preterm birth.

• Risk factors: shorter gestation at the first rupture, smoking, short cervix, low body mass index, bacterial vaginosis, bleeding, cervical surgery.
• Delivery often follows within weeks of the second rupture.
• Planned preventive care starts at the booking visit.

Women with a previous preterm rupture present with leakage of fluid, often with few symptoms. Cervical shortening may cause pelvic pressure or watery discharge before rupture.

• History of preterm rupture or preterm birth.
• Fluid pooling at speculum examination.
• Differential diagnosis: urinary incontinence, vaginal discharge, bacterial vaginosis, cervical insufficiency, mucus plug loss.
• Complications: preterm birth, chorioamnionitis, cord prolapse, abruption, pulmonary hypoplasia, neonatal death, repeated pregnancy loss.

The approach is risk assessment in the next pregnancy, then confirmation of rupture with a sterile speculum test.

• Review of the earlier rupture and delivery record; screen for bacterial vaginosis, urinary infection, chlamydia, gonorrhoea, syphilis and HIV at booking.
• Cervical length by transvaginal ultrasound every 2 weeks from 16 to 24 weeks (below 25 mm is short).
• Speculum examination with nitrazine paper (pH above 6.5) or placental alpha microglobulin 1 or insulin-like growth factor binding protein 1 test for suspected rupture.
• Amniotic fluid index, growth and Doppler scans; full blood count and C-reactive protein for infection.

The principle is prevention by treating infection and shortening, with the usual antibiotic, steroid and magnesium cover when rupture recurs.

• Supportive: stop smoking and alcohol; abstain from intercourse if the cervix is short; avoid heavy lifting; nutrition and weight gain; early admission to a unit with neonatal care when rupture occurs.
• Pharmacological: micronised progesterone 200 mg vaginal at night from 16 to 24 weeks until 36 weeks, which lowers recurrence in women with a previous preterm birth; metronidazole 400 mg oral 12-hourly for 7 days for bacterial vaginosis; amoxicillin 500 mg oral 8-hourly for 7 days for bacteriuria; at rupture before 37 weeks give amoxicillin 500 mg oral 8-hourly plus erythromycin 250 mg oral 6-hourly for 7 days; 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; chorioamnionitis: ampicillin 2 g IV 6-hourly plus gentamicin 5 mg/kg IV once daily.
• Procedures: McDonald cervical cerclage at 12 to 14 weeks for a history of mid-trimester loss, or at 16 to 24 weeks for a cervical length below 25 mm after a previous preterm birth; removal of the cerclage at 36 to 37 weeks, or at once for rupture with infection, labour or bleeding; induction or delivery at 34 weeks if expectant care succeeds without infection.
• Special groups: women with HIV continue tenofovir 300 mg, lamivudine 300 mg and dolutegravir 50 mg oral once daily; RhD negative women give anti-D immunoglobulin 500 IU IM within 72 hours of bleeding.
• Red flags: leaking fluid, pelvic pressure, contractions, fever, foul discharge, bleeding, cervical length falling below 25 mm.
• Follow-up: cervical length every 2 weeks from 16 to 24 weeks; high vaginal swab each trimester; antenatal review every 2 weeks from 24 weeks; plan birth at a unit with neonatal intensive care.