After women immigrate to the UK their maternal health behaviours worsen as their length of residency increases.
The longer ethnic minority women live in the UK the more likely they are to smoke during pregnancy or give up breastfeeding early, concludes a study published on bmj.com.
These findings will have public health implications for countries with large migrant populations, say the authors.
The UK has experienced an increase in immigration over the past 50 years. Previous studies have show that compared with British/Irish white women, women from ethnic minority groups are more likely to breast feed. However, no studies have compared their use of alcohol or tobacco during pregnancy, or whether women's behaviours change with acculturation.
So researchers from the UCL Institute of Child Health in London compared health behaviours during pregnancy (smoking and alcohol consumption) and after birth (initiation and duration of breast feeding) between British/Irish white mothers and mothers from ethnic minority groups.
The study involved over 8588 mothers with singleton children from the millennium cohort study. 6478 British/Irish white mothers and 2110 mothers from ethnic minority groups were interviewed about their maternal health behaviours, generational status and length of residency in the UK.
The researchers found that compared with British/Irish white mothers, mothers from ethnic minority groups were less likely to smoke (15% v 37%) or consume alcohol (14% v 37%) during pregnancy, and were more likely to start breast feeding (86 v 69%) and breast feed for at least four months (40% v 27%).
They also found that among mothers from ethnic minority groups, first and second generation mothers were more likely to smoke during pregnancy, but were less likely to start breast feeding, and less likely to continue breast feeding than immigrants.