Socioeconomic inequalities and adverse pregnancy outcomes in the UK and Republic of Ireland: a systematic review and meta-analysis

OBJECTIVE: There has been an unprecedented rise in infant mortality associated with deprivation in recent years in the United Kingdom (UK) and Republic of Ireland. A healthy pregnancy can have significant impacts on the life chances of children. The objective of this review was to understand the association between individual-level and household-level measures of socioeconomic status and adverse pregnancy outcomes. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Nine databases were searched (Medline, Embase, Scopus, ASSIA, CINAHL, PsycINFO, BNI, MIDRIS and Google Scholar) for articles published between 1999 and August 2019. Grey literature searches were also assessed. STUDY SELECTION CRITERIA: Studies reporting associations between individual-level or household socioeconomic factors on pregnancy outcomes in the UK or Ireland. RESULTS: Among the 82 353 search results, 53 821 titles were identified and 35 unique studies met the eligibility criteria. Outcomes reported were neonatal, perinatal and maternal mortality, preterm birth, birth weight and mode of delivery. Pooled effect sizes were calculated using random-effects meta-analysis. There were significantly increased odds of women from lower levels of occupation/social classes compared with the highest level having stillbirth (OR 1.40, 95% CI 1.23 to 1.59, I(2) 98.62%), neonatal mortality (OR 1.39, 95% CI 1.22 to 1.57, I(2) 97.09%), perinatal mortality (OR 1.39, 95% CI 1.23 to 1.57, I(2) 98.69%), preterm birth (OR 1.41, 95% CI 1.33 to 1.50, I(2) 70.97%) and low birth weight (OR 1.40, 95% CI 1.19 to 1.61, I(2) 99.85%). Limitations relate to available data, unmeasured confounders and the small number of studies for some outcomes. CONCLUSIONS: This review identified consistent evidence that lower occupational status, especially manual occupations and unemployment, were significantly associated with increased risk of multiple adverse pregnancy outcomes. Strategies to improve pregnancy outcomes should incorporate approaches that address wider determinants of health to provide women and families with the best chances of having a healthy pregnancy and baby and to decrease pregnancy-related health inequalities in the general population. PROSPERO REGISTRATION NUMBER: PROSPERO CRD42019140893.