Racial and ethnic disparities in preterm births in infants conceived by in vitro fertilization in the United States.

Objective: The objective of the study was to examine racial and ethnic differences in preterm births in infants conceived by in vitro fertilization (IVF).
Study Design: A retrospective cohort study was conducted of 97,288 singleton and 40,961 twin pregnancies resulting from fresh, nondonor IVF cycles using 2006-2010 data from the Society for Assisted Reproductive Technology Clinic Online Reporting System.
Results: Rates of very early preterm (<28 weeks), early preterm (<32 weeks), and preterm birth (<37 completed weeks) varied across racial and ethnic groups in both singleton and twin pregnancies. In singletons, with white women as the referent, after adjustment of confounding variables, the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of very early preterm birth, early preterm birth, and preterm birth in black women were 4.8 (95% CI, 4.1-5.7), 3.9 (95% CI, 3.4-4.4), and 2.1 (95% CI, 1.9-2.3). Hispanic women had a significantly lower rate of preterm births as compared with black women and similar or slightly higher rates as compared with white women. Native American women were not at an increased risk of any types of preterm births; Asian women were at a reduced risk of preterm twin births (adjusted OR, 0.8; 95% CI, 0.7-0.9).
Conclusion: There exist notable racial and ethnic disparities in preterm births in infants conceived by IVF, suggesting that mechanisms other than socioeconomic disparities contribute to this difference.
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