Abstract
OBJECTIVE: To study the impact of congenital uterine anomalies on reproductive outcomes after in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI)-embryo transfer (ET). METHODS: A retrospective study including a total of 865women with congenital uterine anomalies and 865 age and admission time matched controls who underwent the first IVF/ICSI-ET cycle between January 2010 and December 2019 was conducted. Women with uterine anomalies were classified into canalization defect (complete septate uterus and subseptate uterus) and unification defect (unicornuate uterus, bicornuate uterus, and didelphus uterus) according to the processes of abnormal embryological development. Control women were selected by age (± 1.0 year) and admission time (± 6 months) matched with a 1:1 ratio. The reproductive outcomes were compared between women with uterine anomalies and the controls. The primary outcome was live birth; secondary outcomes were clinical pregnancy, ectopic pregnancy, preterm delivery, and spontaneous pregnancy loss. RESULTS: Compared with women with a normal uterus, women with canalization defects were less likely to experience live birth [84/332 (25.3%) vs 128/332 (38.6%), RR: 0.647, 95% CI 0.513-0.815, P < 0.001]. They also had a lower clinical pregnancy rate [126/332 (38.0%) vs 206/332 (62.0%), RR: 0.829, 95% CI 0.690-0.997, P = 0.046] and experienced a higher first-trimester pregnancy loss rate [25/126 (19.8%) vs 11/206 (5.3%), RR: 2.716, 95% CI 1.393-5.295, P = 0.003]. Compared with women with a normal uterus, women with a unification defect were also less likely to experience live birth [132/533 (24.8%) vs 219/533 (41.1%), RR: 0.713, 95% CI 0.586-0.868, P = 0.001]. Women with a unification defect had lower clinical pregnancy rates [182/533 (34.1%) vs 263/533 (49.1%), RR: 0.813, 95% CI 0.695-0.952, P = 0.010] and increased first-trimester pregnancy loss [36/182 (19.8%) vs 20/263 (7.6%), RR: 3.288, 95% CI 1.776-6.085, P < 0.001]. While uterine anomaly seemed not increase the risk of preterm birth, ectopic pregnancy and second-trimester pregnancy loss. CONCLUSIONS: Both canalization defects and unification defects were associated with lower fertility outcomes, including lower live birth rates, lower clinical pregnancy rates, and higher early miscarriage rates.