Efficacy of Intravenous Paracetamol Infusion versus Intravenous Pentazocine for Labour Analgesia: A Prospective Observational Study

Introduction: Labour pain is recognised as one of the most intense pain experiences. While neuraxial analgesia remains the gold standard, its limited accessibility in resource-constrained settings necessitates the use of systemic agents. Aim: The present study compares the analgesic efficacy, maternal-fetal outcomes, and side-effect profiles of Intravenous (i.v.) paracetamol versus i.v. pentazocine. Materials and Methods: The present prospective observational study was conducted from December 2017 to May 2019 at Kempegowda Institute of Medical Sciences, Bangalore, India. A total of 60 primigravida parturients were divided into two groups: Group A (n=30) received i.v. paracetamol (1g), and Group B (n=30) received i.v. pentazocine (30 mg) during the active phase of labour. Pain relief was assessed using the McGill Pain Intensity Scale at 0, 1, 2, and 4 hours post-administration. Maternal cardiorespiratory parameters, labour duration, mode of delivery, and neonatal outcomes were recorded. Statistical Package for the Social Sciences (SPSS) version 20 was used for statistical analysis. Results: The mean age was 25.3±3.2 years in Group A and 24.9±3.6 years in Group B. Group A, consisting of i.v. paracetamol, demonstrated significantly greater analgesic efficacy (mean McGill score at 2 h: 1.80 vs 2.62; p<0.001) with fewer maternal side-effects (0% vs 16.6%). Neonatal outcomes favoured paracetamol, with one neonate in the pentazocine group having APGAR (Appearance, Pulse, Grimace, Activity, and Respiration) score <7 at one minute (p=0.3) and no cases of APGAR <7 at five minutes in either group. No significant differences were observed in labour duration or delivery mode. Conclusion: Both intravenous paracetamol and pentazocine provided effective analgesia for labour. Paracetamol seemed to be more effective achieving a greater reduction in pain scores compared to pentazocine, and has less maternal side-effects.