Prolonged second stage of labour and the risk for subsequent preterm birth

To assess whether prolonged second stage of labour influences the gestational age at the subsequent delivery.

We performed a retrospective cohort study. Clinical information was retrieved from the McGill Obstetrical and Neonatal Database for the period of January 2001 to February 2008. We evaluated primiparous women with term singleton pregnancies who reached the second stage of labour. Women were divided into two groups, according to the duration of the second stage: delivery after more than three hours of full cervical dilatation, or delivery within three hours. The primary outcome measured was the incidence of spontaneous preterm births at the subsequent delivery.

Among 1818 women whose records were available for analysis, 416 women (22.9%) had a prolonged second stage of labour in their first delivery. Women with a prolonged second stage in their first delivery did not deliver prematurely more often in the successive delivery than those women whose second stage was not prolonged (rate of preterm birth 4.3% in the prolonged second stage group and 5.5% in the normal second stage group; P = 0.3).

In our population of primiparous women with a singleton term delivery, a prolonged second stage of labour lasting more than three hours was not associated with preterm birth at their subsequent delivery.