The risk of twin pregnancies should be minimized in patients with a unicornuate uterus undergoing IVF-ET.

Unicornuate uteri are associated with infertility, miscarriage, preterm delivery and even uterine rupture. The aim of this research was to investigate the effects of unicornuate uterine anomaly on twin pregnancies after in vitro fertilization-embryo transfer (IVF-ET). A total of 206 women with unicornuate uteri (A singleton, B selective reduction (SR) of twins to a singleton, C twins) and 314 women with normal uteri (D SR of twins to a singleton, E twins) who delivered at ≥22 weeks were included. C was associated with a significantly lower live birth rate (adjusted odds ratio (aOR) 0.08, 95% confidence interval (CI), 0.01-0.69) and higher risks of preterm delivery (aOR 11.63, 95% CI, 4.85-27.92), perinatal mortality (aOR 11.43, 95% CI, 1.44-90.57) and low birth weight (aOR 5.92, 95% CI 1.94-18.06) than A, a 15-fold greater risk of preterm delivery (aOR 15.54, 95% CI 3.09-78.28) than B and a greater risk of preterm delivery (aOR 2.76, 95% CI 1.33-5.73) than E. After SR to a singleton, the perinatal outcomes were statistically similar between B and D. These results showed that the risk of twin pregnancies should be minimized in patients with unicornuate uterine anomaly undergoing IVF-ET.