Perinatal mortality and time interval between two deliveries in Lower Saxony, Germany, 2001–2005–an observational study

Obstetrical care is characterised by an uneven distribution of deliveries. Simultaneous deliveries impose naturally an increased workload.

We hypothized that a delivery might by influenced by the previous delivery, if the time interval between the two deliveries would be short enough; i.e. a shorter time interval between two deliveries could be associated with a change in the mode of delivery and possibly with perinatal mortality.

Our aim was

to analyse whether the time interval between two deliveries would be associated with the mode of delivery,

to define a period of dependence of a delivery to the previous one based on these calculations.

to analyse whether a period of dependence would be associated with perinatal mortality.

All singelton deliveries above 24 weeks of gestation and with a live fetus before onset of labour have been included. A total of 317,427 deliveries were analysed.

The time interval between two deliveries shows a strong correlation to the mode of delivery. The Odds Ratio (OR) of a caesarean section decreased until 15–29 min time interval to 0.73 (95% CI 0.69–0.78) and increased to 1.75 (1.68–1.84) after 60–74 min time interval. After a time interval of more than 119 min there was no correlation between time interval and delivery mode observed.

Based on these findings we defined a time interval of 119 min or less as a period of dependency of a delivery from the previous one.

94 (23.4%) out of 402 cases with perinatal mortality have taken place in deliveries with a time interval of 119 min or less. We could show that perinatal mortality is increased in deliveries with a previous delivery of 119 min or less (OR 1.37 (1.08–1.72).

perinatal mortality - time interval between two deliveries