Aim Monochorionic-diamniotic (MCDA) twin pregnancies occur in approximately 1:400 pregnancies and are associated with significant perinatal morbidity and mortality. Whilst there is robust evidence regarding the antenatal management of these pregnancies, the recommended mode of delivery is more controversial with an unquantified risk of acute intrapartum twin-to-twin transfusion syndrome (TTTS). The aim of this study was to assess the outcomes of planned vaginal deliveries in uncomplicated MCDA twin pregnancies.

Methods Retrospective cohort study of MCDA twin pregnancies in a tertiary fetal medicine unit. Clinical notes review was complimented by accessing ultrasound, obstetric and neonatal information systems. Choionicity was confirmed before 16 weeks gestation. Women were offered induction of labour (IOL) between 36–37 weeks gestation if there was no significant growth discrepancy or growth restriction, history of TTTS and the presenting twin was cephalic.

Results 397 MCDA pregnancies were identified between 2008–2013. Early pregnancy losses and unplanned deliveries were excluded leaving 229 pregnancies. There were 173 elective caesarean sections and 56 planned IOL. Of these planned IOL, there were 21 (37.5%) emergency caesarean sections, 3 (5.3%) vaginal deliveries for twin 1/caesarean section for twin 2 and 32 (57%) vaginal deliveries of both twins. From the IOL cohort, 4(3.6%) babies were admitted to the neonatal unit compared to 7 from the elective caesarean section (2.0%) (p = 0.508, odds ratio = 1.765 (95% CI = 0.5–6.1). There were no cases of acute TTTS.

Conclusion Following a strict inclusion protocol, planned elective vaginal delivery appears a safe mode of delivery in MCDA twins.