Objective  To analyze the risk factors of postpartum hemorrhage (PPH) after re-cesarean section in delivery with scar uterus, and to establish a nomogram prediction model for the risk of PPH in delivery puerperas with scar uterine undergoing re-cesarean section.

Methods  A total of 210 cases of pregnant women with uterine scar were selected as research objects, and divided into PPH group (70 cases) and non-PPH group (140 cases) according to whether postpartum bleeding occurred or not. Clinical data of patients were retrospectively analyzed, independent risk factors were screened, prediction models were constructed and presented in nomogram. The model was evaluated using area under the curve (AUC) of receiver operator characteristic (ROC), curve calibration curve and decision curve analysis.

Results  Number of previous abortion (1 time and ≥2 times) (OR=2.838, 95%CI, 1.014 to 8.051, P=0.047; OR=6.843, 95%CI, 2.523 to 18.560, P < 0.001), magnesium sulfate protects fetal history (OR=14.061, 95%CI, 1.173 to 14.061, P=0.027), antepartum haemorrhage (OR=6.977, 95%CI, 1.220 to 39.902, P=0.029), non-term birth (OR=7.737, 95%CI, 2.862 to 20.915, P=0.017), the placenta position (OR=3.370, 95%CI, 1.371 to 8.283, P=0.008), placenta previa (incomplete and complete) (OR=9.210, 95%CI, 1.817 to 46.678, P=0.007; OR=11.407, 95%CI, 3.064 to 42.471, P < 0.001) and placenta implantation (OR=4.029, 95%CI, 1.199 to 13.534, P=0.024) were independent risk factors for PPH in delivery puerperas with uterine scar undergoing re-cesarean section. The AUC of PPH in puerperas with cesarean section predicted by the nomogram was 0.89, the calibration curve fitted well, and the analysis of clinical decision curve showed that the prediction model had clinical practicability.

Conclusion  The nomogram model can effectively evaluate the risk of PPH in delivery puerperas with uterine scar undergoing re-cesarean section, and has good clinical efficacy.