Establishment and Validation of Risk Prediction Model for Postpartum Hemorrhage for Pregnant Women ≥35 Years of Age in Natural Delivery.

ABSTRACT

Context After the age of 35, women's fertility and physical function gradually decline, and this can significantly increase the risks of postpartum hemorrhage (PPH) after delivery. Sufficient exploration of prenatal indicators of PPH for older pregnant women are still lacking. Objective: The study intended to examine the factors influencing postpartum hemorrhage (PPH) in natural delivery for pregnant women ≥35 years of age and to establish a reliable risk-prediction model. Design: The research team performed a retrospective study. Setting: The study took place at Suzhou Ninth People's Hospital in Suzhou, Jiangsu Province, China. Participants: Participants were 351 pregnant women who had undergone a prenatal examination and vaginal delivery at the hospital between January 2019 and October 2022. Groups The research team divided participants into two groups (1) a PPH group, with 52 participants who experienced PPH, and (2) a non-PPH group, with 299 participants who had no PPH. Outcome Measures: The research team (1) conducted single-factor analysis of the two groups' demographic and clinical characteristics; (2) performed multivariate logistic regression analysis to find the factors influencing PPH; (3) built a risk-prediction model based on the results; and (4) analyzed the model's identification ability, proofreading ability, and clinical applicability using a goodness-of-fit test, a receiver operating characteristic (ROC) curve, a calibration curve, and a decision curve. The team used the SPSS 22.0 and R software for statistical analysis. Results: The incidence of PPH was 14.81%, for the 52 out of 351 participants. The PPH group's age (P < .001), rate of pregnancy-induced hypertension (P = .008), length of the third stage of labor (P = .001), and newborn's birth weight (P < .001) were significantly greater and its FIB before delivery was significantly lower than those of the non-PPH group. The high expression of fibrinogen (FIB) before delivery indicates it may be a protective factor against PPH. The multivariate analysis indicated that a greater age (P = .013), pregnancy-induced hypertension (P = .002), a low FIB level (P < .001), a long third stage of labor (P = .012), and a low birth weight for the newborn (P = .006) were all significantly related to PPH. The research team validated the risk-prediction model, which indicated that the model had good recognition ability (AUC = 0.873). The optimal critical value was 34%, and the sensitivity and specificity were 0.869 and 0.826, respectively. In the comparison of the PPH value that the model predicted and the participants' actual PPH incidence (U = -0.006, Brier = 0.089), the deviation of the model wasn't statistically significant (χ2 = 5.964, P = .651). The analysis of the decision curve found that the net benefits for pregnant women ≥35 years of age were higher than those of the other two extreme curves, showing that the model was clinically effective. Conclusions: The PPH risk-prediction model for vaginal delivery for pregnant women ≥35 years of age showed that a greater age, pregnancy-induced hypertension, a lower prelabor FIB, a longer third stage of labor, and a higher birth weight for the newborn were significantly related to the incidence of PPH and that its use could be clinically helpful.