Strengths and Limitations
The strength of our study is the unique and large international Black
patient population at BMC that created the potential to study ethnic
differences within race. We are the first to describe differences in
infertility etiology within a race. Furthermore, the robust chart
analysis used in this study allowed for more accurate stratification of
race and ethnicity as well as confirmation of infertility diagnoses
without sole dependence on ICD-9 coding. The potential for
misclassification bias was limited by using a combination of race, place
of birth, and language to help confirm the racial and ethnic identity of
each woman. By identifying differences in infertility etiologies within
the Black race, our study highlights the importance of ethnic,
environmental, and cultural factors in the genesis of infertility.
Limitations of our study include its retrospective nature and the small
sample size for each ethnic subgroup. We may have been underpowered to
see small differences between groups. We attempted to limit selection
bias inherent in retrospective studies by having two independent
investigators conduct chart reviews. In addition, as ICD-9 codes were
used to identify the potential cohort, it is possible that women with
improper ICD-9 infertility coding were missed. Lastly, the duration of
residency in the United States for Black Haitian or Black African women
could not be ascertained and controlled for to quantify the impact of
U.S. cultural and environmental influences on their infertility
diagnoses. The lack of difference in prevalence of male factor
infertility between groups was limited by our inability to confirm semen
analysis results of male partners of all subjects. Furthermore, the race
and ethnicity of the male partners were not obtained, and we could not
assess whether male partner racial and ethnic differences impacted rates
of infertility.