How a patient’s ethnic background affects her chance of pregnancy, especially with IVF, is a fascinating yet poorly studied area of research. According to a 1995 national survey of family growth, non-Caucasian married women were more likely to experience infertility than Caucasian married women, yet these same non-Caucasian women were less likely to receive any type of infertility treatment—especially treatment with assisted reproductive technologies.
There is very little data in the literature examining ethnicity and its affect upon pregnancy rates with in vitro fertilization (IVF). Ethnic minorities compose a small percentage of patients in the nation’s IVF programs, making it relatively difficult to examine how they respond to various infertility treatments. In the few studies that have examined the affect of ethnicity on IVF pregnancy rates, differing outcomes have been found.
There have been only a few studies specifically comparing IVF success rates between African Americans and Caucasians. The results of two of these studies contradict each other, with one showing that African Americans had decreased pregnancy rates with IVF as compared to Caucasians, and the other finding no difference in pregnancy outcomes with IVF between these two ethnic groups.
Likewise, there are only a few studies directly comparing IVF pregnancy outcomes between Indians and Caucasians. One shows a trend towards decreased pregnancy rates in Indian women and finds that Indian women were significantly more likely to have their cycle cancelled as compared to Caucasian women. In comparison, another study found no significant difference in IVF pregnancy rates between Indians and Caucasians. A more recent study has shown that Asian ethnicity was an independent predictor of poor outcome with IVF. There have been no studies examining IVF pregnancy outcomes in Hispanics in comparison to any other ethnic groups.
When I was in training, I published the first study comparing IVF outcomes among multiple ethnic groups. It was a retrospective study utilizing a data set that was the result of the collaboration between three IVF centers in the Boston area: Boston IVF, Brigham and Women’s Hospital IVF Center, and Reproductive Science Center.
We retrospectively reviewed the cycles of 1,135 women undergoing IVF between 1994 and 1998. Only the first IVF cycle for each couple was reviewed. Ethnicity was self-reported. Women who categorized themselves as having a mixed ethnic background were excluded. Caucasians made up the majority of the patients, constituting 91.5% of the patient population. African Americans, Asians, and Hispanics accounted for 4%, 3%, and 1.5% of the population, respectively.
African American women had a significantly higher BMI and weight in comparison to both Caucasian and Asian women. In addition, we found that Caucasians weighed significantly more than Asians. However, there was no difference in the mean BMI between these groups.
African Americans had a significant increased number of total past pregnancies in comparison to Caucasian and Asian women. However, there was no difference in the previous live births among the different ethnic groups.
Duration of infertility was increased in Hispanics in comparison to Caucasians and African Americans. The mean duration of infertility was 58 months for Hispanics in comparison to 38 months and 35 months for Caucasians and African Americans, respectively.
Day 3 FSH levels did not vary among the different ethnicities. There was no significant difference among the various ethnicities for the most causes of infertility. However, we found that African American women were more likely to have tubal factor as a cause of their infertility than Caucasians, with 51% of African Americans having tubal factor in comparison to 22% of the Caucasian patient population.
The majority of IVF cycle characteristics were not influenced by the ethnicity of the patients. African Americans and Asians had significantly higher levels of estradiol on the day of HCG than Caucasians. There was no significant difference among ethnicities for any of the cycle outcomes. The rates of successful live births did not change with ethnicity.
There are many reasons for the differing results of all of these studies, including the fact that some studies were performed in states where IVF coverage is mandated by health insurance while other studies were not, which obviously affects the socioeconomic milieu of the patients. Some studies looked at all IVF cycles vs. just studying the patients’ first IVF cycle. When multiple cycles are included in the analysis, data on IVF outcomes may be confounded by the results for patients who unsuccessfully underwent repetitive cycles of IVF.
Our study was limited by its retrospective nature and the small sample size of the ethnic minorities.
In order to better understand how ethnicity affects IVF outcome, it will be necessary to study a larger number of minority patients. In these studies, it is important that all ethnicities be included. If racial differences do exist, IVF treatment protocols could be adjusted to improve the success rates for patients of all ethnic backgrounds. Therefore, further exploration in this area is necessary and very important.