Uterine atony at a tertiary care hospital in Pakistan: a risk factor analysis

To identify risk factors for uterine atony following assisted or unassisted vaginal delivery.

This hospital based case control study was done at The Aga Khan University Karachi, Pakistan. Cases were defined as all women with uterine atony within 24 hours of an assisted or unassisted vaginal delivery. Controls were based on women with normal assisted or unassisted vaginal delivery without uterine atony. Data abstracted form the medical records; adjusted odds ratios were estimated by multiple logistic regression.

Factors having a significant association with uterine atony were gestational diabetes mellitus (odds ratio 7.6, 95% CI 6.9-9.0, p = 0.003) and a prolonged second stage of labour in multiparas (odds ratio 4.0, 95% CI 3.1-5.0, p = 0.002). No associations were found with high parity, age, preeclampsia, augmentation of labour, antenatal anemia and a history of poor maternal or perinatal outcomes.

Among previously documented risk factors for uterine atony, only a prolonged second stage of labour in multiparas was found to be significant in this study. Gestational diabetes mellitus, a previously undocumented factor, has also been identified as an independent risk factor. Multiparity and age were not found to be significant risk factors. The study underlines the importance of confirming these findings for better prevention and management of uterine atony.