Does the preterm birth racial disparity persist among black and white IVF users?

Investigators from the National Institutes of Health and Shady Grove Fertility found that among women having a singleton live birth resulting from in vitro fertilization (IVF) that black women are at higher risk for lower gestational age and preterm delivery than white women.¹ The study results were presented at the American Society for Reproductive Medicine (ASRM) 2018 annual meeting (October 6 to 10, Denver, Colorado).

Kate Devine, MD, coinvestigator of the retrospective cohort study said in an interview with OBG Management that “It’s been well documented that African Americans have a higher preterm birth rate in the United States compared to Caucasians and the overall population. While the exact mechanism of preterm birth is unknown and likely varied, and while the mechanism for the preterm birth rate being higher in African Americans is not well understood, it has been hypothesized that socioeconomic factors are responsible at least in part.”² She added that the investigators used a population of women receiving IVF for the study because “access to reproductive care and IVF is in some way a leveling factor in terms of socioeconomics.”

Details of the study. The investigators reviewed all singleton IVF pregnancies ending in live birth among women self-identifying as white, black, Asian, or Hispanic from 2004 to 2016 at a private IVF practice (N=10,371). The primary outcome was gestational age at birth, calculated as the number of days from oocyte retrieval to birth, plus 14, among white, black, Asian, and Hispanic women receiving IVF.

Births among black women occurred more than 6 days earlier than births among white women. The researchers noted that some of the shorter gestations among the black women could be explained by the higher average body mass index of the group (P<.0001). Dr. Devine explained that another contributing factor was the higher incidence of fibroid uterus among the black women (P<.0001). But after adjusting for these and other demographic variables, the black women still delivered 5.5 days earlier than the white women, and they were more than 3 times as likely to have either very preterm or extremely preterm deliveries (TABLE).¹

Research implications. Dr. Devine said that black pregnant patients “perhaps should be monitored more closely” for signs or symptoms suggestive of preterm labor and would like to see more research into understanding the mechanisms of preterm birth that are resulting in greater rates of preterm birth among black women. She mentioned that research into how fibroids impact obstetric outcomes is also important.

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