Cyclic AMP and segmental epidural analgesia during labour.

The blood cyclic AMP level was determined just before, during and after induced labour in 27 healthy women. To achieve complete pain relief during the first stage of labour, 14 of them were given segmental epidural analgesia at the height of Th 10-12. The remaining parturients served as controls. Cyclic AMP was above the normal non-gravid level before induction in both groups. In the control group the cyclic AMP content decreased during the first stage of labour, then it increased and reached a peak at the moment of delivery. These changes were, however, not significant. In the epidural group the cyclic AMP level rose significantly during the first stage, and also reached its peak at the moment of delivery. There was a statistically significant difference between the groups at a cervical dilatation of 6-8 cm. After delivery the cyclic AMP rapidly declined to its initial value in both groups. The possible role of the decreased uterine contractions after the block in the increase of the cyclic AMP is discussed.