RESULTS
A total of 1278 women were identified by the BMC Clinical Data Warehouse database with ICD9 codes for infertility from 2005 to 2015. Among these women, 662 met inclusion criteria, and their charts were reviewed. Infertility was confirmed in 99 Black American, 110 Black Haitian, 61 Black African, and 88 White American women (Figure 1). Black women were on average of similar age to White Americans at the time of their diagnosis (33 and 32 years old respectively, p=0.064) (Table 1). However, after stratification into Black ethnic subgroups, this similarity was not retained, and Black Haitians and Black Africans were on average older (35 years old) at the time of diagnosis compared to Black Americans and White Americans (31 and 32 years old respectively, p<0.001). Body mass index (BMI) was higher among Black compared to White American women (p=0.008), and this difference was maintained after a subgroup analysis of Black ethnic groups, with the highest BMI seen among Black American women (p=0.004).
There was no significant difference in parity or marital status between all Black women combined compared to White American women. However, subgroup analysis of Black ethnic subgroups showed differences in both parity and marital status between groups. In terms of parity, 41% of African women were multiparous compared to 25% of Haitian, 17% of Black American, and 18% of White American women (p<0.001). African women (62%) were more likely to be married than Black American (19%), Haitian (41%), and White American (48%) women (p=0.007). A greater proportion of Black women (32%) were unemployed compared to White American women (10%, p=0.003). Subgroup analysis comparing White women and Black ethnic subgroups continued to show this difference, with Black Africans having the highest rate of unemployment (43%), followed by Black Haitians (35%, p<0.001). In addition, Black women were more likely to be uninsured or on Medicaid compared to White American women (55% and 14% respectively, p<0.001). This difference was maintained when Black ethnic groups were stratified with the highest uninsured rate seen among Black Haitians (61%) and Black Africans (61%, p<0.001).
Infertility diagnoses fell into 6 categories: anovulation/polycystic ovary syndrome (PCOS), tubal Factor, uterine Factor, male Factor, premature ovarian failure (POF), and unexplained. Table 2 and Figure 2 summarize the prevalence of the various infertility diagnoses in the racial/ethnic groups. As above, an initial analysis was performed comparing all Black women (i.e., by combining ethnicities) with White American women. A significantly higher proportion of Black women (19.6%) had infertility secondary to tubal factor compared to White American women (6.8%, p=0.03). In addition, White American women (29.5%) had a significantly higher frequency of unexplained infertility compared to Black women (13.3%, p=0.006).
With regard to comparisons with racial/ethnic subgroups, Black American women had a higher frequency of infertility secondary to anovulation/PCOS (56.5%, p=0.001) compared to White American (39.8%), Black Haitian (25.5%) and Black African women (21.3%). Black African women had a higher percentage of infertility secondary to POF (18.0%) compared to the other groups that ranged between 2.7 and 3.4% (p=0.0004). A comparison of day 3 FSH) levels, showed no difference in rates of elevated day 3 FSH level ≥10 mIU/ml among all Black women (10%) compared to White women (4.5%, p=0.09). However, the stratified analysis of Black ethnic subgroups showed a greater percentage of African (16%) and Haitian (16%) women with elevated day 3 FSH compared to Black (1.0%) and White (4.5%) American women (p=0.001, Table 1). White American women had a lower frequency of infertility secondary to tubal factor (6.8%) than the other groups of women, especially in comparison to Black Americans (18.2%) and Black Haitians (25.5%, p=0.03). Black Haitians (20.9%) and Black Africans (16.4%) had a higher frequency of infertility secondary to Uterine Factor than either Black (7.1%) or White Americans (9.1%, p=0.03). There were no differences in the frequency of male factor infertility among the groups. In Black Haitian and Black African women, infertility diagnoses were more evenly distributed compared to the other two groups, with anovulation/PCOS (25.5% and 21.3%), tubal factor (25.5% and 11.5%) and uterine factor (20.9% and 16.4%) contributing to the majority of infertility diagnoses (Table 2).
Tables 3 and 4 present the final unadjusted and adjusted multivariate logistic regression analyses. The regression analyses were adjusted for factors known to influence fertility, including age, BMI, parity, and SES. There were no differences in prevalence of male factor infertility among the groups, so only infertility factors affecting females were included in the analysis. Table 3 summarizes the prevalence of the various infertility diagnoses in the White/overall Black groups and shows the adjusted and unadjusted analyses between racial groups. Tubal factor infertility was more common in Black compared to White women (19.6% and 6.8% respectively, p=0.04), but this difference was not retained in the adjusted analysis (p=0.15). There were no other significant differences in infertility etiologies between Black and White races after adjusting for potential confounders. In the multivariate model comparing infertility diagnoses between the White and individual Black ethnic groups (Table 4), Black American women had five times the odds of having PCOS/anovulation compared to Black African women (95% CI 1.4, 17.0). In addition, compared to Black African women, higher odds of tubal factor infertility were observed in Black American (aOR=4.7, 95% CI=1.2, 18.7) and Black Haitian women (aOR=4.0, 95% CI=1.4, 14.0). No other significant differences were seen among specific ethnic groups for the diagnoses of premature ovarian failure, uterine factor, and unexplained infertility.