Relationship Between Body Mass Index and the Incidence of Perineal Tears in Primigravid Women: A Retrospective Cross-Sectional Study at a Hospital in Mexico

INTRODUCTION: Perineal tears represent one of the main complications of vaginal delivery, with immediate and long-term consequences for maternal health. Although several factors have been associated with their occurrence, the role of maternal body mass index (BMI) remains controversial. OBJECTIVE: This study aims to evaluate whether there is a significant difference in the incidence of perineal tears among primigravid women with different BMI categories. METHODS: A retrospective cross-sectional study was conducted between March 2022 and February 2024 at the General Hospital of Specialties "Dr. Javier Buenfil Osorio" (Campeche, Mexico). A total of 180 (100%) primigravid women with term pregnancies were included and categorized according to BMI as normal weight, overweight, or obese. The incidence of perineal tears was compared among the groups. RESULTS: The overall prevalence of perineal tears was 56.7% (102 patients). Tear rates were similar across BMI categories: normal weight with 58.3% (35 patients), overweight with 51.7% (31 patients), and obese with 60.0% (36 patients). No statistically significant differences were found (p = 0.622). Additionally, no correlation was identified using Kendall's Tau-b test (p = 0.854). CONCLUSION: No significant association was observed between maternal BMI and the incidence of perineal tears in primigravid women. Other obstetric factors may play a more relevant role.