Black women have worse IVF outcomes. New science helps explain why

By Sarah Elizabeth Richards edited by Tanya Lewis

For the past two decades, fertility specialists have wrestled with a troubling question: Why do Black people have lower live birth rates after in vitro fertilization (IVF) treatment than white people?

Researchers have proposed several explanations, such as the fact that Black women have higher rates of fibroids—noncancerous growths that can interfere with embryo implantation, the delicate process by which an embryo burrows into the uterine lining and stays there. Another possibility is that their bodies simply don’t respond as well to IVF stimulation drugs—medications that push the ovaries to produce multiple mature eggs at once that are later inseminated to make embryos that can be transferred to the uterus in the hopes of establishing a pregnancy.

To narrow in on the causes, researchers at the University of Pennsylvania aimed to break down the IVF process step by step. They wanted to see if they could offer insight into other researchers’ earlier inconsistent findings suggesting that Black women needed higher doses of medication or generated fewer viable embryos.

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In their recent study, which was published in Fertility and Sterility, the researchers analyzed a total of more than 246,000 ovarian stimulation cycles, 7 percent of which were in Black women, to compare how women of different racial or ethnic groups responded and to measure how many of those cycles resulted in live births. The new analysis found that Black participants responded slightly better than people of other racial or ethnic groups to ovarian stimulation drugs, and their eggs produced high-quality embryos that could be used for implantation. This was after the researchers adjusted for participants’ age at retrieval, body mass index, hormone levels and infertility diagnoses in data that were collected nationally between 2017 and 2019 by the Society for Assisted Reproductive Technology, a U.S. professional organization that tracks IVF outcomes from fertility clinics.

Nevertheless, the Black women in the study had a lower rate of live birth—about 45 percent, compared with about 60 percent for white women.

“There’s clearly something happening that’s a roadblock to getting to the ultimate goal of bringing home a baby,” says Iris Tien-Lynn Lee, an ob-gyn at the University of Pennsylvania and lead author of the study. “I think it’s an issue with implantation,” she hypothesizes.

But what the cause is, exactly, is still unclear. The study authors also acknowledged the potential role of higher rates of uterine fibroids, as well as endocrine-disrupting chemicals, such as those found in hair relaxers, and exposure to environmental contaminants that other studies have shown is higher in Black populations.

“It’s a useful finding because it’s important to know there are more things to be investigated, but the most frustrating thing is that we don’t know what, exactly,” says Tia Jackson-Bey, a reproductive endocrinologist at Reproductive Medicine Associates of New York and an expert on fertility care access, who was not involved in the study. “We would need a more complete dataset to tease out any meaningful differences based on race,” she says. Other promising areas of research include looking at aspects of the mental and physical health of the person trying to get pregnant, including their uterine microbiome and cardiovascular health; the latter could affect uterine blood flow.

That information is also valuable because it offers insight into how Black women are treated in the health care system, adds Tarun Jain, a professor of obstetrics and gynecology at Northwestern University Feinberg School of Medicine. “Black women in health care experience worse outcomes in general, whether it’s maternal mortality, infertility treatment or preterm birth,” says Jain, who has written about structural barriers that account for disparities in fertility medicine. “We need to address these inequities at a broader level.”

That means acknowledging social determinants of health—the nonmedical conditions that shape health, including racism, income inequality, and disparities in health insurance coverage and access to healthy food. Jain co-authored a 2020 study that found that Black women were more likely to report that their income and race were barriers to getting infertility treatment. They also traveled twice as far as white women to reach a fertility clinic.

According to a 2025 opinion of the practice committee of the American Society for Reproductive Medicine, as a result of factors such as these, Black women are more likely than white women to be older when they first see a fertility doctor and are more likely to be diagnosed with diminished ovarian reserve—meaning their egg quality and quantity has declined with age, and the odds of a successful treatment are worse. (Jain is a member of the practice committee and helped develop the opinion report.)

“It’s important to know it’s not the stimulation drugs,” says Jain, referring to the University of Pennsylvania researchers’ finding. “But a lot more work needs to be done to understand the other factors and the implicit biases that may still exist.”

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