Lack of change in birthweights of infants by generational status among Indian, Pakistani, Bangladeshi, Black Caribbean, and Black African mothers in a British cohort study.

AIM To test the hypothesis that an intergenerational increase would occur in birthweights of babies born to UK-born compared with overseas-born (migrant) minority women. METHOD Live singleton births to mothers present at the 1991 Census in a national longitudinal study were classified by mother's country of birth and ethnic origin as reported in the census. During 1983-2000, 52,554 White, 1788 Indian, 1538 Pakistani, 995 Bangladeshi, 300 Black Caribbean, and 299 Black African live singleton births were identified. Mean birthweights were adjusted for maternal age, socio-economic circumstances, gender, year of birth, and birth order. RESULTS Adjusted mean birthweights were: 3400 g (95% CI: 3395, 3405) for infants of UK-born White mothers; 3033 g (95% CI: 2980, 3087) of UK-born Indian mothers and 3066 g (95% CI: 3034, 3097) of migrant Indian mothers; 3110 g (95% CI: 3049, 3172) of UK-born Pakistani mothers and 3123 g (95% CI: 3087, 3159) of migrant Pakistani mothers; 3026 g (95% CI: 2922, 3130) of UK-born Bangladeshi mothers and 3110 g (95% CI: 3076, 3145) of migrant Bangladeshi mothers; 3268 g (95% CI: 3177, 3359) of UK-born Black Caribbean mothers and 3238 g (95% CI: 3089, 3388) of migrant Black Caribbean mothers; and 3167 g (95% CI: 3004, 3330) of UK-born Black African mothers and 3302 g (95% CI: 3208, 3395) of migrant Black African mothers. The proportions of low birthweight infants (<2500 g), generally greater among migrant mothers than White UK-born mothers, were similar by generational status within the ethnic groups. CONCLUSION There are no significant differences in mean birthweights of infants by generational status among mothers from these main ethnic minority groups in the UK.