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.