Introduction: In-vitro-fertilization (IVF) is an independent risk factor for placenta previa (PP). Our aim was to study this link by comparing the clinical characteristics and placental histology of pregnancies complicated by PP in IVF versus unassisted pregnancies.
Methods: A retrospective-cohort study of deliveries with PP between 2008 and 2021. Placental histology, obstetric and neonatal outcomes were compared between IVF and unassisted pregnancies. Included, were singleton deliveries complicated by PP at gestational weeks (GA) >24.
Results: A total of 182 pregnancies were included - 23 IVF pregnancies (IVF group) and 159 unassisted pregnancies (Control group). The control group was characterized by higher gravidity (p = .007) and parity (p < .001) and a trend of more past cesarean deliveries, whereas the IVF group- by a higher rate of nulliparity (p < .001) and diabetes mellitus (p = .04). The control group was characterized by a higher rate of placental weight below the 10th percentile (47.8 versus 13.9%, p = .001) and by a trend of a lower overall placental weight. No differences were noted in maternal and fetal vascular lesions.
Discussion: While PP in non-assisted pregnancies is probably associated with previous CDs, in IVF it is more "sporadic," and may complicate any index pregnancy. A lower placental weight was more prevalent in the control group, supporting the concept that pregnancies complicated by PP following IVF can be attributed to initial abnormal location of placentation, rather than an underlying pathological uterine segment of implantation. Nevertheless, IVF and unassisted pregnancies entail similar perinatal outcomes in cases of PP.
Keywords: Placenta previa (PP); in vitro fertilization (IVF); placental histology; placentation.