Is there a relation between operative birth and postpartum infection? - an observational longitudinal study

Abstract Overview and Aims: In high-income countries, 5% of puerperal deaths are due to postpartum infections. Although there is clear evidence that antibiotic prophylaxis before caesarean section reduces the incidence of infection, there is less evidence in operative birth. The aim of this study was to compare the prevalence of puerperal infection between operative birth and spontaneous vaginal birth, finding independent risk factors for it. Study design: A prospective observational study was carried out at the Obstetrics Department of a public hospital. Population: Patients with a vaginal birth were enrolled in this study, and for each operative birth a spontaneous vaginal birth was recruited in a ratio of 1:1. Methods: Data was collected in the first 24 hours after the birth and 6 weeks after birth, when a telephone survey was performed to assess the occurrence of infection. Results: 385 postpartum women were included, 35 (9.1%) developed postpartum infection. The prevalence of infection in the operative birth group was higher (13.4% vs. 4.7%; p=0.003). In the same group most women were nulliparous (74.7% vs. 45.5%, p<0.001), the median duration of membrane rupture and active phase of labor was higher (5.5 hours, vs. 3.0 hours, p<0.001; 4.8 hours, vs. 3.0 hours, p<0.001), more episiotomies were performed (92.8% vs. 37.7%; p<0.001) and fewer grade I or II perineal lacerations occurred (6.2% vs. 25.1%; p<0.001). In the logistic regression, anemia was the only independent predictor of infection (p<0.001; correctly predicted cases=90.8%). Conclusion: Although the prevalence of postpartum infection was higher after operative birth, it was not an independent risk factor. This reiterates the need to continue the investigation of operative birth contribution to postpartum infection. Before considering generalizing antibiotic prophylaxis, maybe each institution needs to analyze local data and think about how to control other possible risk factors for infection.