Context The number of women who achieve pregnancy through assisted reproductive technology (ART), including in vitro fertilisation and embryo transfer (IVF-ET), is increasing worldwide. Placenta-mediated diseases associated with ART, such as gestational hypertension, preeclampsia, disorders of placental implantation, and placental abruption, are also increasing. Aims To determine the association between placental pathologies and IVF-ET in women with preterm births. Methods This retrospective cohort study examined archived placenta specimens of women who achieved pregnancy through either spontaneous conception or IVF-ET. In total, 1677 women with singleton pregnancies who gave birth consecutively between 20 and 37 weeks of gestation at Seoul National University Bundang Hospital and underwent placental pathologic evaluation between April 2013 and October 2018 were included. Data from all pathologic reports were reviewed. Key results The IVF-ET group had a higher median maternal age and rate of nulliparity than the natural conception group. The incidence rate of obstetric complications, except preterm premature rupture of membranes and placenta previa, was similar in both groups. The IVF-ET group had a higher incidence rate of placental infarction than the natural conception group (26.4% vs 16.4%, P = 0.012). Multivariate logistic regression analysis indicated that IVF, hypertensive disorders, and fetal growth restriction were significantly associated with placental infarction. Conclusions IVF-ET was independently associated with the risk of placental infarction in women with preterm births. Implications The use of IVF-ET may cause abnormal placental formation with an increased risk of anatomical and vascular pathology, which are observed in preterm deliveries and may contribute to pregnancy complications.

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