Cesarean births, previous history of postpartum hemorrhage (PPH), fetal macrosomia increase the risk of PPH, suggests a recent study published in the September 2022 issue of the European Journal of Obstetrics & Gynecology and Reproductive Biology.¹ Nulliparous women were also at high risk of developing PPH after delivery.

Researchers from University College Cork and INFANT Research Centre in Cork, Ireland attempted to find out if certain factors could predict the risk of PPH, defined as blood loss of 1000 ml or more after delivery, in women with singleton pregnancies. For this, they obtained data of all 6077 women who delivered a single child at the Cork University Maternity Hospital (CUMH) in 2019, which is a part of the National Maternal and Newborn Clinical Management System (MN-CMS); 5807 women were included in the analysis.

The factors examined were age of the mother, BMI, parity, history of previous cesarean birth, gestational age, fetal macrosomia, mode of delivery, assisted fertility and history of PPH. A risk prediction nomogram was developed using these variables to assess individualised risk assessment for PPH. Internal validation of the data was done by bootstrapping to reduce overfitting.

There were 270 (4.65%) cases of PPH among the women included in the analysis. Maternal BMI, parity, assisted fertility, macrosomia, mode of delivery and history of PPH were significantly associated with PPH. Four were found to best predict the chances of women developing PPH after childbirth. These included parity particularly nulliparity, mode of delivery especially operative vaginal delivery, cesarean section (emergency and prelabour), macrosomia and history of PPH. Regarding internal validation, the researchers write, “The original apparent C-statistic was 0.751 (95% CI: 0.721, 0.779) suggesting good discriminative performance. There was minimal optimism adjustment to the C-statistic after bootstrapping, indicating good internal performance (optimism adjusted C-statistic: 0.748).” When the data was subjected to external validation using data from 6691 single deliveries with 255 instances of PPH at the same hospital during the year 2020, the results of the two were comparable indicating good reproducibility.

This study has identified four variables that were most predictive of the individual risk of PPH, a major cause of maternal morbidity and mortality. Identification of at-risk women facilitates timely implementation of appropriate measures for their active management.

Reference

1. Gillian M Maher, et al. Predicting risk of postpartum haemorrhage during the intrapartum period in a general obstetric population. Eur J Obstet Gynecol Reprod Biol. 2022 Sep;276:168-173. doi: 10.1016/j.ejogrb.2022.07.024.