The characteristics of the second stage of labour in 25,069 singleton deliveries in the North West Thames Health Region, 1988

Abstract

Objective: To define the contemporary characteristics of the second stage of labour in one Health Region.

Design: Retrospective analysis of a regional obstetric database.

Setting: Seventeen maternity units in the North West Thames Health Region.

Subjects: Selected from 36,727 consecutive singleton deliveries in 1988. The analysis was confined to the 25,069 women delivered of an infant of at least 37 weeks gestation with a cephalic presentation following the spontaneous onset of labour.

Main outcome measures: Second stage duration, obstetric intervention and maternal and fetal morbidity.

Results: The duration of the second stage and the use of operative intervention were strongly negatively associated with parity and positively associated with the use of epidural analgesia. Maternal age, fetal birthweight and maternal height were also independently associated with the duration of the second stage. There were small but significant differences in the characteristics of women using epidural analgesia and those using alternative methods of pain relief. Parous women using epidural analgesia behaved in a similar manner to nulliparae without epidurals. Despite the longer second stages observed in women using epidural analgesia there appeared to be no significant increase in fetal morbidity. Within the region the epidural rate in individual units positively correlated with the overall forceps rate, the rate of caesarean section in the second stage of labour and the duration of the second stage.

Conclusions: In our study the duration of the second stage in women not using epidural analgesia was similar to previous findings, but in those using epidural analgesia, the duration of the second stage was longer than has been reported previously, possibly reflecting a more conservative approach to operative intervention. Survival analysis indicates that in multiparae not using epidural analgesia the likelihood of spontaneous vaginal delivery after 1 h in the second stage was low, but in those multiparae using epidural analgesia and in all nulliparae there was no clear cut-off point for expectation of spontaneous delivery in the near future; they continue to give birth at a steady rate over several hours. While maternal and fetal conditions are satisfactory, intervention should be based on the rate of progress rather than the elapsed time since full cervical dilatation.