Maternal and fetal risks associated with prolonged latent phase of labour.

A pregnancy cohort study was undertaken to assess the fetal, maternal and obstetric risks associated with the prolonged latent phase of labour. One hundred and fifty cases (latent phase >8 hours) were compared with 100 controls (latent phase <8 hours). Data were collected from hospital records. There were more nulliparas in the case group (73% vs. 39%; P<0.0001). Cases required oxytocin augmentation (62% vs. 17%; P<0.0001) and caesarean section (29% vs. 6%; P<0.0001) more frequently than controls. Thick meconium staining of the liquor was more frequent in cases (15% vs. 5%; P<0.05), as were 5-minute Apgar scores less than 7 (17% vs. 3%; P<0.001) and admission to the neonatal unit (22% vs. 1%; P<0.0001). Prolonged latent phase is associated with increased risks for obstetric intervention and poor fetal outcome. The optimal management of prolonged latent phase is still unknown and requires further study by means of randomised controlled trials.