Preterm Labour Management with Glyceryl Trinitrate Patch and Isoxsuprine: A Longitudinal Study

Abstract

Introduction: Nitric oxide donors in the form of nitroglycerine and β-mimetic drugs (Isoxsuprine hydrochloride) are commonly used in managing preterm labour. It is one of the most challenging obstetric complications encountered by obstetricians, as well as preterm neonates for paediatricians. Preterm labour refers to the onset of uterine contractions of sufficient strength and frequency to effect progressive dilatation and effacement of the cervix between 20 and 37 weeks of gestation. Aim: To compare the effects of transdermal Glyceryl Trinitrate (GTN) with Isoxsuprine in terms of maternal complications, perinatal outcomes, and their tocolytic effectiveness. Materials and Methods: A hospital-based longitudinal study was conducted in the Department of Obstetrics and Gynaecology at JNU Medical College and Research Centre, Jaipur, Rajasthan, India. The study duration of the study was one year, from March 2022 to February 2023. A total number of 100 cases of preterm labour were enrolled and equally divided into two groups: Groups A (GTN patch) and group B (Isoxsuprine) with a defined dosing schedule. Singleton pregnancies with intact membranes and gestational age of 26-36 weeks were included in the study, metting the diagnostic criteria for preterm labour. Both the groups received pharmacological intervention, and outcome measures such as success rate of treatment (i.e., prolongation of labour),. maternal side effects, and foetal outcomes {Neonatal Intensive Care Unit (NICU) admission and Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) score) were measured and evaluated. Predefined parameters and other data were tabulated in Microsoft Excel and statistical analysis was performed using Statistical Package for Social Sciences (SPSS) version 20.0. The Chi-square test was applied to identify significant differences. Results: The incidence of preterm labour was highest in the age group of 21-30 years (76% in Group A and 70% in Group B) among patients treated with nitroglycerine and isoxsuprine, respectively. The mean prolongation of pregnancy in the nitroglycerine group was 21.42 days, and in the isoxsuprine group, it was 16.22 days (p=0.042). The most common side effect in the nitroglycerine group was headache (60%), while in the isoxsuprine group, it was maternal hypotension (24%). The mean APGAR score in Group A and Group B was 8.18 and 8.06, respectively. It was observed that 24% of newborns in the nitroglycerine group and 36% in the isoxsuprine group required NICU admission. The success rate was 90% in the nitroglycerine group and 80% in the isoxsuprine group. Conclusion: Both drugs were effective in prolonging pregnancy for the first 48 hours, but nitroglycerine was found to be slightly better in terms of success rate. Nitroglycerin was more acceptable to patients with preterm labour, as it did not have to be administered through painful injections.