In vitro fertilization increases the risk of placenta accreta spectrum in second-trimester pregnancy loss: A retrospective cohort study

The risk of placenta accreta spectrum (PAS) associated with in vitro fertilization and embryo transfer (IVF-ET) in the context of mid-trimester pregnancy loss remains unclear. This study aimed to investigate the impact of IVF-ET on the incidence of PAS and identify the risk factors among women undergoing pregnancy loss following fetal demise or inevitable miscarriage during the second trimester. In our retrospective cohort study, we analyzed women who experienced second-trimester fetal loss due to fetal demise or inevitable miscarriage at the Sixth Affiliated Hospital of Sun Yat-sen University between January 2013 and October 2023. The participants were categorized into IVF-ET (n = 93) and non-IVF-ET (n = 134) groups. The primary outcome was the incidence of PAS, which was diagnosed clinically or pathologically. Secondary outcomes included morbid PAS, postpartum hemorrhage, and other complications. Our results indicated that the IVF-ET group had a significantly greater risk of experiencing PAS (39.8% vs 17.9%, P < .001) and morbid PAS (17.2% vs 3.7%, P < .001) compared to the non-IVF-ET group. The median postpartum blood loss was greater (230.0 [120.0-600.0] mL vs 120.0 [70.0-200.0] mL, P < .001), and the rates of postpartum hemorrhage (30.1% vs 12.7%, P = .001) and retained products of conception persisting >4 weeks (38.7% vs 19.4%, P < .001) were also greater in the IVF-ET group. Multivariate analysis revealed IVF-ET (adjusted odds ratio [aOR] = 3.13; P = .002), a hysteroscopic history (aOR = 3.58; P = .02), and uterine abnormalities (aOR = 3.74; P = .02) as independent risk factors for PAS. In the IVF-ET group, compared with fresh embryo transfer, cryopreserved embryo transfer (aOR = 3.52; P = .01) was associated with a markedly higher risk of PAS (50.9% vs 22.2%, P = .006) and remained an independent risk factor after adjustment (aOR = 3.52; P = .01). Among women with mid-trimester pregnancy loss, those who underwent IVF-ET, especially cryopreserved embryo transfer, had a high risk of PAS, leading to increased hemorrhagic morbidity and complications. These findings highlight the need for enhanced preoperative assessment, vigilant management, and strategies to preserve fertility in this high-risk population.