Impact of sperm morphology on the likelihood of pregnancy after intrauterine insemination

Objective To determine whether there is a difference in ongoing pregnancy rates (PRs) between patients undergoing IUI with strict sperm morphology ≤4% compared with >4% on initial semen analysis. Design Retrospective chart review with multivariate analysis. Setting Academic outpatient reproductive center. Patient(s) A total of 408 couples with male and/or female factor infertility and known strict sperm morphology (SSM). Intervention(s) A total of 856 IUIs with partner's sperm (IUI-P). Main Outcome Measure(s) Ongoing PRs based on ultrasound documentation of intrauterine pregnancy with fetal heart tones. Result(s) There is no statistically significant difference in per cycle PRs when comparing patients with a strict sperm morphology of ≤4% versus >4% who undergo IUI-P (17.3% vs. 16.7%; odds ratio 0.954, 95% confidence interval 0.66–1.37). Multiple potential confounding factors were assessed using multivariate analysis. Conclusion(s) Strict sperm morphology ≤4% is not associated with lower PRs in couples undergoing IUI-P, and thus should not be the sole reason for advancing to IVF.