A comparison of the effect of spinal analgesia and sedo-analgesia on maternal cortisol levels during labour
Background: Labour pain is a complex stimulus known to trigger and enhance adaptive responses in both mother and foetus.
Objective: This study was to determine whether, or not, alleviation of pain with single-shot spinal analgesia has an influence on cortisol levels during labour.
Methods: Forty ASA I and II multiparous women undergoing spontaneous vaginal delivery were randomised to receive single spinal analgesia (Group SSA) or intravenous sedo-analgesia (Group SA). Using the L3-4 interspace, patients received intrathecal heavy bupivacaine 2.5 mg with fentanyl 25 micrograms, after which they were returned immediately in the supine position with left uterine displacement (Group SSA). Sedoanalgesia (intravenous pentazocine 30 mg with promethazine 25 mg) was administered to Group SA. Maternal cortisol levels were measured before and after administration of analgesia at interval of 30 minutes during labour and in the postpartum period. Labour pain was assessed using the verbal pain score.
Results: There was no difference in the baseline cortisol levels (SA – 338.05±8.24 ng/dl and SSA – 340.14±6.29 ng/dl), p=0.124. At the 1st hour of labour, the cortisol level in the SA group showed a steep rise compared to the SSA group, (p=0.0001). The difference in the cortisol levels at 2nd and 3rd hours between the groups was statistically significant (P=0.0001). Following delivery, both groups showed step-wise fall in cortisol levels. The differences in the levels remained statistically significant (p=0.0001) until the 18th hour after onset of labour.
Conclusion: The study showed that single shot spinal analgesia provided a short duration but profound pain relief in labour. Lower maternal cortisol levels during labour were found in those that received single shot spinal analgesia.
Keywords: Cortisol level, labour, single shot spinal analgesia, sedo-analgesia, multiparous women