Maternal and early childhood health and social outcomes of migrants in high-income countries and the impact of policies that restrict access to healthcare; a systematic review and meta-analysis.

Background: The "healthy migrant effect" suggests migrants experience better health than local populations despite socioeconomic disadvantage. Its relevance to maternal and child health is uncertain. This systematic review and meta-analysis examined outcomes among migrant women and children in high-income countries (HICs), and the impact of restrictive healthcare policies. Methods: Studies published between 2014 and 2024 comparing outcomes for foreign-born migrant women and children (up to five years) with local-born populations were included. Quality was assessed using the Newcastle-Ottawa Scale. Pooled odds ratios (ORs) were calculated using random-effects meta-analyses. Findings: Fifty-one moderate- or high-quality studies (67,471,879 participants across 16 HICs) were included. Migrant women were more likely to be from minority ethnic groups, have lower educational and socioeconomic status, and be older and multiparous. Migrants had higher odds of emergency caesarean birth (OR=1.24, 95%CI=1.16-1.33), food insecurity (OR=2.49, 95%CI=1.24-5.96), perinatal depression/anxiety (OR=1.67, 95%CI=1.10-2.54), intimate partner violence (OR=2.20, 95%CI=1.31-3.72), and low Apgar scores (OR=1.37, 95%CI=1.19-1.56). Odds of low birth weight were slightly lower (OR=0.95, 95%CI=0.90-1.00). Associations persisted under restrictive healthcare policies. No significant differences were found in maternal mortality, severe maternal morbidity, preterm birth, fetal loss, neonatal intensive care use, or vaccination coverage. There is a notable lack of evidence on longer-term child health outcomes. Interpretation: The "healthy migrant effect" may not apply during the perinatal period. Migrant women face significant health inequities, exacerbated by exclusionary policies. Further research, particularly into long-term child outcomes and in inclusive healthcare settings, is needed to inform equitable policy and practice.