Risk Factors for Postpartum Hemorrhage Following Vaginal Deliveries in China: A Case-Control Study of Second Births After IUD Removal.

OBJECTIVE

This study aims to evaluate the predictive value of risk factors for postpartum hemorrhage (PPH) following vaginal delivery, with a special focus on the impact of intrauterine device (IUD) usage in the context of recent policy changes allowing more childbirths in China.

METHODS

A total of 6879 women who underwent vaginal deliveries from January 2021 to December 2023 in the Lianyungang regional maternal care system and met the inclusion and exclusion criteria were enrolled. A case-control design was employed, comprising 524 women with PPH (blood loss ≥500 mL) 24h after giving birth and an equal number of controls (blood loss <500 mL) matched on a 1:1 ratio. Univariate and multivariate logistic regression analyses, alongside ROC curve analysis, were conducted to identify risk factors for PPH.

RESULTS

Univariate analysis revealed significant differences in age (OR = 1.86, 95% CI: 1.35-2.57, P < 0.01), number of miscarriages (OR = 1.97, 95% CI: 1.46-2.65, P < 0.001), gestational week, number of fetuses, weight of the second child (OR = 10.78, 95% CI: 7.88-14.75, P < 0.001), placental adhesion, and uterine atony (OR = 2.40, 95% CI: 1.60-3.61, P < 0.001). No significant differences were observed regarding occupation, educational level, mode of first delivery, IUD use and duration, and presence of gestational diabetes or hypertension (P > 0.05). Multivariate logistic regression identified age, number of miscarriages, weight of the second child, and uterine atony as independent risk factors for PPH (P < 0.05). ROC curve analysis showed that the combined predictive value of these factors was superior, with an AUC of 0.805 for the combined predictive model.

CONCLUSION

PPH is influenced by advanced maternal age, multiple miscarriages, high birth weight, and uterine atony. IUD use may not independently impact the likelihood of PPH under the conditions studied.