Risk of adverse perinatal outcomes among African-born Black women in California, 2011-2020

Safyer McKenzie-Sampson; Rebecca J Baer; Brittany D Chambers Butcher; Laura L Jelliffe-Pawlowski; Deborah Karasek; Scott P Oltman; Corinne A Riddell; Elizabeth E Rogers; Jacqueline M Torres; Bridgette Blebu

doi:10.1097/EDE.0000000000001745

Risk of adverse perinatal outcomes among African-born Black women in California, 2011-2020

Epidemiology. 2024 Mar 29. doi: 10.1097/EDE.0000000000001745. Online ahead of print.

Authors

Safyer McKenzie-Sampson^{1

2}, Rebecca J Baer^{1

2

3

4

5

6

7

8

9

10}, Brittany D Chambers Butcher⁶, Laura L Jelliffe-Pawlowski^{1

3}, Deborah Karasek^{3

7}, Scott P Oltman^{1

3}, Corinne A Riddell⁸, Elizabeth E Rogers⁹, Jacqueline M Torres^{1

3}, Bridgette Blebu¹⁰

Affiliations

¹ Department of Epidemiology & Biostatistics, University of California San Francisco School of Medicine.
² Department of Pediatrics, Stanford University School of Medicine.
³ UCSF California Preterm Birth Initiative, University of California San Francisco School of Medicine.
⁴ Department of Obstetrics, Gynecology and Reproductive Sciences, University of California San Francisco School of Medicine.
⁵ Department of Pediatrics, University of California San Diego.
⁶ Department of Human Ecology, University of California Davis.
⁷ School of Public Health, Oregon Health & Science University and Portland State University.
⁸ Divisions of Biostatistics and Epidemiology, School of Public Health, University of California Berkeley.
⁹ Department of Pediatrics, University of California San Francisco School of Medicine.
¹⁰ Department of Obstetrics and Gynecology, Lundquist Institute/Harbor-UCLA, University of California, Los Angeles.

PMID: 38567905
DOI: 10.1097/EDE.0000000000001745

Abstract

Background: African-born women have a lower risk of preterm birth and small for gestational age (SGA) birth compared to United States (US)-born Black women, however variation by country of origin is overlooked. Additionally, the extent that nativity disparities in adverse perinatal outcomes to Black women are explained by individual-level factors remains unclear.

Methods: We conducted a population-based study of non-anomalous singleton live births to US- and African-born Black women in California from 2011-2020 (n=194,320). We used age-adjusted Poisson regression models to estimate risk of preterm birth and SGA, and reported risk ratios (RR) and 95% confidence intervals (CI). Decomposition using Monte Carlo integration of the g-formula computed the percentage of disparities in adverse outcomes between US- and African-born women explained by individual-level factors.

Results: Eritrean women (RR 0.4; 95%CI: 0.3, 0.5) had the largest differences in risk of preterm birth and Cameroonian women (RR 0.5; 95% CI: 0.3, 0.6) in SGA birth, compared to US-born Black women. Ghanaian women had smaller differences in risk of preterm birth (RR 0.8; 95%CI: 0.7, 1.0) and SGA (RR 0.9; 95% CI 0.8, 1.1) compared to US-born women. Overall, we estimate that absolute differences in socio-demographic and clinical factors contributed to 32% of nativity-based disparities in the risk of preterm birth and 26% of disparities in SGA.

Conclusions: We observed heterogeneity in risk of adverse perinatal outcomes for African- compared to US-born Black women, suggesting that nativity disparities in adverse perinatal outcomes were not fully explained by differences in individual-level factors.