The effect of segmental epidural analgesia on maternal prolactin during labour.

Maternal plasma prolactin (PRL) concentrations were determined during the course of induced labours in 18 normal parturients. Every second mother was given segmental epidural analgesia for pain relief during the first stage of labour and the remaining parturients served as controls. The maternal PRL level declined during labour in both groups, which contrasts with the increased output seen in nonpregnant patients subjected to stress. The lowest levels were reached during the first stage of labour. The reduction in PRL levels was statistically significant in the control group but not in the epidural group of patients.