Anencephaly and obstetric outcome beyond the age of viability

Objective To review the obstetric impact and natural history of anencephalic pregnancies beyond the age of viability. Study design A retrospective chart review of all cases with a prenatal diagnosis of anencephaly who delivered after 24 weeks' gestation during the period 1990 until 2016. Obstetric outcomes including mode of delivery, live births, shoulder dystocia, antepartum haemorrhage (APH), postpartum haemorrhage (PPH) and uterine rupture were studied. Results A total of 42 cases were studied. The average gestational age at diagnosis was 22 weeks (range 10-41). The average gestational age at birth was 36 weeks (range 25-44 weeks). Induction of labour was performed in 55% (23/42) of the cases. Livebirths were documented in 40% (17/42) of the cases. The average birth weight was 1597±746 g. The rate of vaginal birth was 69% (29/42), the overall rate of caesarean section was 31% (13/42), with a primary caesarean section in 31% (4/13) and a repeat caesarean section in 69% (9/13) of the patients. There were two cases of shoulder dystocia. No other complications were encountered. Conclusion Overall, anencephaly is not associated with an increased risk of obstetric complications; however, there is a tendency towards delivery via repeated caesarean section in women with a previous uterine scar and anencephaly. The prenatal counselling of potential obstetric outcomes could be of robust value for parents who opt to continue with anencephalic pregnancies.