Risk factors and assisted reproductive outcomes in infertility patients with concomitant endometrial polyps

Objective To investigate the high risk factors of endometrial polyps (EPs) in infertile patients and its impact on the pregnancy outcome after embryo transfer. Methods A case-control trail was conducted on the infertility patients who undergoing embryo transfer in our hospital for the first time after hysteroscopy from January 2016 to December 2022.Their clinical data were collected and retrospectively analyzed.Univariate and stepwise logistic regression analyses were used to identify the risk factors for EPs, and the impact of polyps on the pregnancy outcomes of assisted reproductive pregnancy was analyzed with propensity score matching (PSM) at a 1:2 ratio. Results A total of 388 patients diagnosed with EPs and undergoing hysteroscopic endometrial polypectomy were assigned into the EPs group, and 2 163 non-polyp patients were into the non-EPs group.Univariate analysis showed statistical differences were observed in age[31(29, 34)vs 31(28, 33), P=0.002], history of pelvic inflammatory disease (42.78%vs 64.17%, P=0.000), age at menarche[14(12, 14)vs 13(12, 14) years old, P=0.000], number of pregnancies[0(0, 1)vs 1(0, 2), P=0.000], primary infertility (60.30%vs 50.20%, P=0.000), duration of infertility[4(2.1, 6.0)vs 4(2.0, 6.0) years, P=0.002], concomitant endometriosis (9.53%vs 6.52%, P=0.032), concomitant uterine fibroids (11.85%vs 6.93%, P=0.001), and basal estrogen level[38.12(27.00, 59.00)vs 36.00(25.00, 53.00)μg/L, P=0.016]between the 2 groups.Logistic stepwise regression analysis indicated that age (OR=1.082, 95%CI: 1.053~1.113, P < 0.05), primary infertility (OR=2.951, 95%CI: 1.990~4.376, P < 0.05), and elevated basal estrogen (OR=1.003, 95%CI: 1.001~1.005, P < 0.05) were risk factors for EPs.The postoperative biochemical pregnancy rate (59.28%vs 52.70%), clinical pregnancy rate (53.09%vs 45.48%), and live birth rate (43.81%vs 35.82%) were significantly higher in the matched EPs group than the non-EPs group (P < 0.05).No statistical difference was observed in pregnancy outcome in the patients with different polyp locations and sizes.The patients with multiple polyps had an obvious higher rate of early miscarriage than those with single polyp (17.27%vs 7.29%, P < 0.05), while those with recurrent polyps also had a higher rate of early miscarriage than those with primary polyps (27.78%vs 11.23%, P < 0.05). Conclusion Age, primary infertility, and elevated basal estrogen are risk factors for EPs in infertility patients, while hysteroscopic endometrial polypectomy prior to embryo transfer results in improved pregnancy outcomes in those with EPs.The location and size of endometrial polyps have weak impact on pregnancy outcomes following embryo transfer, but, the presence of multiple or recurrent polyps may elevate the risk of early miscarriage.