Low BMI is associated with poor IUI outcomes: a retrospective study in 13,745 cycles.

PurposeTo evaluate the association between body mass index (BMI) and pregnancy outcomes in women receiving intrauterine insemination (IUI) treatment.MethodsThe study included 6407 women undergoing 13,745 IUI cycles stratified by BMI. Cox regression was used to analyze the association between BMI and cumulative live births across multiple IUI cycles. A generalized estimating equation (GEE) was used to analyze the live birth rate per cycle.ResultsCompared with normal-weight women (n = 4563), underweight women (n = 990) had a lower cumulative pregnancy and live birth rate (20.71% vs 25.93% and17.17% vs 21.61%, respectively), while overweight women (n = 854) had a higher cumulative pregnancy and live birth rate (31.97%, 26.58%). Adjusted for confounders, the hazard ratio (HR) for achieving live birth following up to a maximum of four IUI cycles was 0.80 (95% CI: 0.67-0.95), comparing underweight with normal weight. In the GEE analyses, low BMI was also associated with a lower per-cycle birth rate (OR 0.79, 95% CI: 0.66-0.95), with adjustment for cycle-specific parameters, including ovarian stimulation, endometrial thickness, and follicular diameter.ConclusionLow BMI is associated with poor IUI outcomes.