The impact of different sperm preparation methods on clinical pregnancy and live birth rates in intrauterine insemination cycles: a retrospective single-center cohort study

Abstract

Objective: To assess the impact of 2 different sperm preparation methods, density gradient centrifugation and simple wash, on clinical pregnancy and live birth rates in intrauterine insemination (IUI) cycles with and without ovulation induction.

Design: Retrospective single-center cohort study.

Setting: Academic fertility center.

Patients: In total, 1,503 women of all diagnoses sought IUI with fresh-ejaculated sperm.

Exposure: Cycles were divided into 2 groups on the basis of sperm preparation technique: density gradient centrifugation (n = 1,687, unexposed group) and simple wash (n = 1,691, exposed group).

Main outcome measures: Primary outcome measures consisted of clinical pregnancy and live birth rates. Furthermore, adjusted odds ratios and 95% confidence intervals for each outcome were calculated and compared between the 2 sperm preparation groups.

Results: Odds ratios did not differ between density gradient centrifugation and simple wash groups for clinical pregnancy and live birth (1.10 [0.67-1.83] and 1.08 [0.85-1.37], respectively). Additionally, when cycles were stratified using ovulation induction rather than adjusted for, no differences in clinical pregnancy and live birth odds were noted between sperm preparation groups (gonadotropins: 0.93 [0.49-1.77] and 1.03 [0.75-1.41]; oral agents: 1.78 [0.68-4.61] and 1.05 [0.72-1.53]; unassisted: 0.08 [0.001-6.84] and 2.52 [0.63-10.00], respectively). Furthermore, no difference was seen in clinical pregnancy or live birth when cycles were stratified using sperm score or when the analysis was limited to first cycles only.

Conclusion: Overall, no difference was noted in clinical pregnancy or live birth rates between patients who received simple wash vs. density gradient-prepared sperm, suggesting similar clinical efficacy between the 2 techniques for IUI. Because the simple wash technique is more time-efficient and cost-effective compared with the density gradient, adoption of this technique could lead to comparable clinical pregnancy and live birth rates for IUI cycles, although optimizing teamwork flow and coordination of care.

Keywords: Intrauterine insemination; density gradient; semen processing; sperm preparation; sperm wash.