Racial/ethnic disparity in severe maternal morbidity among women who conceived by in vitro fertilization.

Background: In vitro fertilization (IVF) as a fertility treatment is associated with adverse perinatal outcomes. Racial/ethnic disparity in severe maternal morbidity (SMM) in women who conceived by IVF is understudied. Objective: To examine differences in the association between race/ethnicity and SMM between women who conceived spontaneously and those who conceived using IVF. Methods: We included all singleton live births and stillbirths in the United States, 2016-2021; data were obtained from the National Center for Health Statistics. Maternal race/ethnicity included non-Hispanic White (NHW), non-Hispanic Black (NHB), American Indian and Alaska Native (AIAN), Asian, Pacific Islander (PI), Hispanic, and mixed-race categories. The SMM composite outcome included eclampsia, uterine rupture, peripartum hysterectomy, blood transfusion, and intensive care unit (ICU) admission. We used logistic regression to adjust for potential confounders (such as age, education, parity, prepregnancy body mass index, smoking during pregnancy, chronic hypertension, and preexisting diabetes) and to assess modification of the association between race/ethnicity and SMM by IVF. Results: The study population included 21,585,015 women: 52% were NHW, 15% NHB, 0.8% AIAN, 6% Asian, 0.2% PI, 24% Hispanic, and 2% were of mixed race. IVF was used by 183,662 (0.85%) women; the rate of the SMM composite outcome was 18.5 per 1000 deliveries and 7.9 per 1000 deliveries in the IVF and spontaneous conception groups, respectively (unadjusted rate ratio 2.34, 95% confidence interval [CI] 2.26-2.43). In women with spontaneous conception, NHB, Asian and mixed-race women had elevated odds of SMM compared with NHW women (adjusted odds ratio [aOR]=1.39, 95% CI 1.37-1.41; aOR=1.04, 95% CI 1.02-1.07; and aOR=1.42, 95% CI 1.38-1.46, respectively). Racial/ethnic disparities in SMM and its components were not different between the IVF and spontaneous conception groups for the mixed-race category. NHB and Hispanic women had significantly higher aORs for uterine rupture/intrapartum hysterectomy compared with NHW women in the IVF group, while Asian women had a higher aOR for ICU admission compared with NHW women in the IVF group. Conclusion: Women who conceived by IVF have a greater than two-fold higher risk of SMM and this higher risk is evident across all racial/ethnic groups. However, NHB and Hispanic women who conceived by IVF had a higher risk of uterine rupture/hysterectomy, and Asian women who conceived by IVF had a higher risk of ICU admission. Our results warrant further investigation examining pregnancy and postpartum care issues among racial/ethnic minority women who conceive using IVF.