Relationship of Total Motile Sperm Count and Percentage Motile Sperm to Successful Pregnancy Rates Following Intrauterine Insemination1

Purpose: This study sought (i) to investigate the relationship between Postwash total motile sperm count and Postwash percentage motile sperm in predicting successful intrauterine insemination and (ii) to determine the minimal Postwash total motile sperm count required to achieve pregnancy with intrauterine insemination. Methods: Five hundred four women, who underwent 1636 intrauterine insemination cycles with their partner's sperm for infertility treatment from 1993 through 1995, were included in this retrospective study. All patient charts were reviewed for age, infertility etiology, ovarian stimulation regimens, semen characteristics, and treatment outcome. To determine the relationship between total motile sperm count and intrauterine insemination outcome, patients were grouped as (1) less than 0.5 million, (2) 0.5 to l million, (3) 1 to 5 million, (4) greater than 5 million, and (5) greater than 20 million. Results: Similar live birth rates (per cycle) were seen among the Postwash total motile sperm count groups: group 1, 3.5%; group 2, 2.4%; group 3, 7.0%; group 4, 6.9%; and group 5, 7.0% (P = 0.37). However, regardless of the postwash total motile sperm count, the Postwash motility predicted intrauterine insemination success at a cutoff value of 40%. Conclusions: The percentage of Postwash sperm motility, and not the Postwash total motile sperm count, can predict successful intrauterine insemination outcome. Such information can be useful in counseling patients regarding their chance of success with intrauterine insemination acrd in determining when alternate methods of assisted reproduction may be a better approach.