Efficacy of Intravenous Infusion of Acetaminophen for Intrapartum Analgesia.

Introduction: The intensity of pain experienced by women in labour, has been found to affect the progress of labour, foetal well-being and maternal psychology. Adverse effects associated with commonly used opioids for providing intrapartum analgesia have created a need for an alternative non-opioid drug.

Aim: To evaluate the efficacy of an intravenous infusion of 1000 mg of acetaminophen as an intrapartum analgesic.

Materials And Methods: The present prospective single-centre, single blind, placebo-controlled randomized interventional study was conducted in Department of Obstetrics and Gynaecology in Vardhaman Mahavir Medical College & Safdarjung Hospital over a period of six months from September 2014 to March 2015. After receiving the ethical clearance and written informed consent. The first 200 consecutive parturients fulfilling the inclusion criteria were recruited into the study. Women were then randomised to receive either intravenous 1000 mg (100ml) of acetaminophen (Group A, n=100) or 100 ml normal saline (Group B, n=100). Primary outcome assessed was effectiveness of acetaminophen to provide an adequate amount of analgesia, as measured by a change in Visual Analogue Scale (VAS) pain intensity score at various times after drug administration. Secondary outcomes measured were duration of labour, need for additional rescue analgesia and presence of adverse maternal or foetal effect.

Results: There was pain reduction at 1 and 2 hours in both groups (p<0.001). However, it was more significant in the acetaminophen group, especially at 1 hour. Duration of labour was shortened in both the groups, without any maternal and foetal adverse effects.

Conclusion: Intravenous acetaminophen is an efficacious non-opioid drug for relieving labour pain without any significant maternal and foetal adverse effects.