Delivery outcomes after day and night onset of labour

To describe the outcome of night onset of labour as compared with the day onset of labour to investigate if labour that begins at night is more efficient.

Retrospective review of labour and delivery data.

A large United Kingdom maternity service.

Over the period of 10 years, there were 30,022 deliveries, of which 19,842 were studied.

A United Kingdom maternity department database was used to identify deliveries over a 10-year period, and the delivery outcomes were retrieved from these records. The 19,842 labours were divided into two categories: night onset (22.00-06.00 h) and day onset (10.00-18.00 h).

Rates of operative intervention, augmentation, epidural usage and labour duration.

A significant difference in delivery outcome was noted (P=0.004) with the night-onset labours having more normal deliveries (83.6% vs. 82.5%), fewer caesarean sections (8.7% vs. 10.1%), fewer labour augmentations with syntocinon (14.9% vs. 19.5%, P<0.001), fewer artificial rupture of membranes (14.1% vs. 15.6% P<0.001) and a significantly shorter mean first stage duration (4 h 58 min vs. 5 h 7 min, P<0.05). The proportion of women from each group who delivered between 09.00 and 17.00 h was 3660 (31.1%) in the night-onset group and 2414 (30%) in the day-onset group (χ2=1.3, P=NS) Conclusions: Labours that start at night appear to be more efficient than labours that start during the day.