The impact of assisted reproductive technology on the risk of postpartum hemorrhage: Difference by the mode of delivery and embryo transfer

Aim: The frequency of postpartum hemorrhage (PPH) is increasing in developed countries, and some reports suggest that assisted reproductive technology (ART) increases various perinatal complications, including PPH. We investigated whether the effect of ART pregnancies on the incidence of PPH is modified by the mode of delivery.Methods: A retrospective cohort study was performed. We analyzed the medical records of 2914 pregnant women, including 411 pregnancies achieved by ART, which were delivered in our hospital from 2017 to 2020. PPH was defined as hemorrhage exceeding the 90th percentile of blood loss per the mode of delivery and number of fetuses. Multivariable logistic regression analysis was used to assess the association between ART and PPH. Propensity score-matched analyses were used to assess the difference in the incidence of PPH by the mode of delivery.Results: As previously reported, multivariable logistic regression analysis showed that ART pregnancy is an independent risk factor for PPH. Propensity score-matched analysis for with and without ART showed a 3.39-fold higher incidence of PPH for ART pregnancy in the vaginal delivery group (p < 0.001).Conclusions: The effect of ART pregnancies on the incidence of PPH differed depending on the mode of delivery. Only in vaginal delivery, ART pregnancy increased the incidence of PPH.