Racial and Ethnic Differences in Pregnancy Rates Following Intrauterine Insemination with a Focus on American Indians

Background: No research exists on American Indian pregnancy rates following infertility treatment. Most racial/ethnic fertility research has focused on pregnancy following in vitro fertilization, with only rare studies looking at intrauterine insemination (IUI). The objective of our study was to compare fecundability following IUI by race/ethnicity, with a special focus on American Indians.

Methods: This was a retrospective analysis of subjects undergoing IUI July 2007-May 2012 at a university-based infertility clinic. The primary outcome was positive pregnancy test, with a secondary outcome of ongoing pregnancy/delivery (OP/D). We calculated risk ratios (RR) and 95% confidence intervals (CI) using cluster-weighted generalized estimating equations method to estimate modified Poisson regression models with robust standard errors to account for multiple IUI cycles in the same patient.

Results: A total of 663 females (median age 32) undergoing 2007 IUI cycles were included in the analysis. Pregnancy rates overall were 15% per IUI cycle. OP/D rates overall were 10% per IUI cycle. The American Indian patients had significantly lower pregnancy (RR 0.34, 95% CI 0.16-0.72) and OP/D rates (RR 0.33, 95% CI 0.12-0.87) compared to non-Hispanic whites when patient and cycle characteristics were controlled. Pregnancy and OP/D rates for blacks, Asians, and Hispanics did not differ from those of non-Hispanic whites.

Conclusions: Our finding of lower IUI treatment success among American Indian patients is novel, as no published studies of assisted reproductive technology or other fertility treatments have examined this subgroup separately. Further investigation of patient and clinical factors that may mediate racial/ethnic disparities in fertility treatment outcomes is warranted.