Effects of race and ethnicity on perinatal outcomes in high-income and upper-middle-income countries: an individual participant data meta-analysis of 2 198 655 pregnancies

IPPIC Collaborative Network

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Abstract

Background: Existing evidence on the effects of race and ethnicity on pregnancy outcomes is restricted to individual studies done within specific countries and health systems. We aimed to assess the impact of race and ethnicity on perinatal outcomes in high-income and upper-middle-income countries, and to ascertain whether the magnitude of disparities, if any, varied across geographical regions. Methods: For this individual participant data (IPD) meta-analysis we used data from the International Prediction of Pregnancy Complications (IPPIC) Network of studies on pregnancy complications; the full dataset comprised 94 studies, 53 countries, and 4 539 640 pregnancies. We included studies that reported perinatal outcomes (neonatal death, stillbirth, preterm birth, and small-for-gestational-age babies) in at least two racial or ethnic groups (White, Black, south Asian, Hispanic, or other). For our two-step random-effects IPD meta-analysis, we did multiple imputations for confounder variables (maternal age, BMI, parity, and level of maternal education) selected with a directed acyclic graph. The primary outcomes were neonatal mortality and stillbirth. Secondary outcomes were preterm birth and a small-for-gestational-age baby. We estimated the association of race and ethnicity with perinatal outcomes using a multivariate logistic regression model and reported this association with odds ratios (ORs) and 95% CIs. We also did a subgroup analysis of studies by geographical region. Findings: 51 studies from 20 high-income and upper-middle-income countries, comprising 2 198 655 pregnancies, were eligible for inclusion in this IPD meta-analysis. Neonatal death was twice as likely in babies born to Black women than in babies born to White women (OR 2·00, 95% CI 1·44–2·78), as was stillbirth (2·16, 1·46–3·19), and babies born to Black women were at increased risk of preterm birth (1·65, 1·46–1·88) and being small for gestational age (1·39, 1·13–1·72). Babies of women categorised as Hispanic had a three-times increased risk of neonatal death (OR 3·34, 95% CI 2·77–4·02) than did those born to White women, and those born to south Asian women were at increased risk of preterm birth (OR 1·26, 95% CI 1·07–1·48) and being small for gestational age (1·61, 1·32–1·95). The effects of race and ethnicity on preterm birth and small-for-gestational-age babies did not vary across regions. Interpretation: Globally, among underserved groups, babies born to Black women had consistently poorer perinatal outcomes than White women after adjusting for maternal characteristics, although the risks varied for other groups. The effects of race and ethnicity on adverse perinatal outcomes did not vary by region. Funding: National Institute for Health and Care Research, Wellbeing of Women.

Original languageEnglish
Pages (from-to)2049-2062
Number of pages14
JournalThe Lancet
Volume400
Issue number10368
DOIs
StatePublished - 10 Dec 2022

Bibliographical note

Funding Information:
The IPPIC Data Repository was originally set up by funding from the National Institute for Health Research Health Technology Assessment Programme (14/158/02 and 17/148/07). We acknowledge all researchers in the IPPIC Collaborator Network who contributed data to this IPD meta-analysis, including the original teams involved in the collection of the data, and participants who took part in the research studies. The authors alone are responsible for the views expressed in this Article and they do not necessarily represent the views, decisions, or policies of the institutions with which they are affiliated.

Publisher Copyright:
© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license

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