The Pregnancy Outcomes Comparison on Natural or Controlled Ovarian Stimulation Cycles in Intrauterine Insemination Treatment: An Analysis of 8,893 Cycles

Objective: To evaluate the intrauterine insemination pregnancy outcomes both in nature and controlled ovarian stimulation cycles Design: Retrospective analysis. Setting: A single university medical center. Intervention: After controlled ovarian stimulation or nature cycle follicle monitoring, IUI performed 24-36 hours after ovulation triggering. Main Outcome Measure: The pregnancy rate, live birth rate, miscarriage rate. Result: The clinical pregnancy and live birth rate was statistically significantly higher in the stimulated cycles than nature cycles as well as that of abortion rate. The pregnancy rate and live birth rate of combination CC with HMG and LE with HMG was higher than other protocols (P0.05). Conclusion: Ovarian stimulation could significant increase pregnancy and live birth rate accompany with a higher abortion rate compared with nature cycles in intrauterine insemination treatment. Letrozole combined gonadotropins stimulation protocols showed higher pregnancy rates and live birth rate in comparison to natural cycle and other stimulation protocols. The ovary stimulation was failed to improve the pregnancy outcome of women who have good natural cycles. Nature cycles were still favorable to recommend for safety factors.