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Abstract Study question Is there an adverse impact of idiopathic infertility diagnosis on placental pathology among singleton pregnancies conceived with fertility treatments? Summary answer Idiopathic infertility does not increase rates of placental abnormalities and exhibits distinctive associations within the inflammatory and vascular spectrum of placental pathology. What is known already Pregnancies resulting from fertility treatments are often considered to be at higher risk for placenta-mediated obstetric complications and subsequent adverse perinatal outcomes. Treatment induced hormonal changes altering the endometrial milieu, along with embryo manipulation and culture conditions, may impact the processes of implantation, decidualization, trophoblast invasion, and placental vascularization. Nevertheless, the impact of infertility diagnoses on placental pathology among singleton pregnancies conceived with fertility treatments has not been elucidated, and whether idiopathic infertility alters the risk of placental abnormalities remains unknown. Study design, size, duration Retrospective review of placental pathology data from 1205 singleton livebirths conceived with fertility treatments (899 IVF, and 306 OI±IUI cycles) between 01/2004 and 04/2022. Placenta pathology was reviewed by one expert pathologist and classified as anatomic, inflammatory, infectious, and vascular including any features of fetal (FVM) or maternal (MVM) vascular malperfusion, using the Amsterdam Workshop Consensus definitions. Placental abnormalities were compared between idiopathic infertility (IdI, n: 269) and all other, non-idiopathic infertility (non-IdI, n:936) diagnoses. Participants/materials, setting, methods Primary outcomes: anatomic, inflammatory, infectious, and vascular placental abnormalities. Parametric, and non-parametric tests were used as appropriately; odds ratios (OR) with 95% confidence intervals (95%CI) were assessed through logistic regression, adjusting for maternal age, body mass index (BMI, kg/m2), race, parity, gestational age, neonatal gender, treatment type, gestational diabetes, and hypertensive disorders. Analyses were further stratified by OI±IUI vs IVF treatments the latter further stratified into fresh and frozen embryo transfers (FET). Main results and the role of chance Mean age, BMI, and AMH did not differ between groups, and neither did placental weight at term. Overall, unadjusted rates of inflammatory, infectious, and vascular abnormalities did not differ between groups (12.6% vs 11.4%, p 0.568; 22.0% vs 19.1%, p 0.256; 54.5% vs 58.6%, p 0.186, respectively). However, a higher rate of anatomic abnormalities was noted among IdI patients (32.8% vs 27.1%, p 0.044, IdI vs. non-IdI, respectively). When adjusting for potential confounders, no differences were noted between groups regarding inflammatory, infectious, and vascular abnormalities, and the observed difference in anatomic abnormalities lost its significance adjOR(95%CI); inflammatory: 0.98(0.94-1.03), infectious: 1.03(0.98-1.09), vascular: 0.96(0.90-1.02), and anatomic: 1.02(0.96-1.08), non-IdI: ref. Similarly, when separating OI±IUI from FET and fresh IVF cycles, adjOR(95%CI) revealed no differences in anatomic, infectious, and vascular abnormalities between groups OI±IUI: 0.97(0.85-1.1), 0.97(0.87-1.08), 0.99(0.87-1.12); FET: 1.08(0.94-1.24), 1.07(0.94-1.23), 1.04(0.98-1.11) and, fresh IVF: 1.06(0.98-1.15), 1.04(0.96-1.13), 0.96(0.87-1.07), for anatomic, infectious, and vascular, respectively. However, lower odds of inflammatory abnormalities were noted among fresh IVF but not among FET or OI±IUI cycles in IdI adjOR (95%CI); fresh IVF: 0.95(0.91-0.99), FET: 1.09(0.98-1.21), OI±IUI: 0.97(0.87-1.08), non-IdI: ref. Interestingly, among vascular abnormalities studied in the programmed FET cycles, MVM showed a difference between the groups adjOR(95%CI) 0.90(0.85-0.96), non-IdI: ref. Limitations, reasons for caution This study is limited by its retrospective design. The reported findings are from an infertile population undergoing treatments and thus not easily generalizable to natural conceptions. Other factors, such as environmental, nutritional, and lifestyle, might alter a patient’s individual pregnancy risk for placental abnormalities. Wider implications of the findings Overall, idiopathic infertility does not appear to increase the risk for placental abnormalities. However, it may impact placental pathology in a unique way, within the vascular and inflammatory spectrum, which might differ from that of other infertility diagnoses, and might be further altered by the treatment protocol. Trial registration number Not Applicable
Dimitriadis et al. (Mon,) studied this question.