Objective To examine differences between Pakistani and White British women in relation to socioeconomic position, lifestyle and health-related pregnancy characteristics, and to determine whether these differences vary depending on the woman's, her partner's and both of their parents’ place of birth.

Design Prospective cohort study.

Setting Bradford, UK

Participants 3656 Pakistani and 3503 White British women recruited to the Born in Bradford study.

Main outcome measures Socioeconomic position (employment status; level of education; receipt of benefits; housing tenure), lifestyle characteristics (body mass index (BMI) at the start of pregnancy; smoking during pregnancy) and health-related pregnancy characteristics (hypertensive disorders of pregnancy; gestational diabetes; fasting glucose, postload glucose and fasting insulin at ∼27 weeks gestation).

Results Fewer Pakistani women were employed (OR 0.17, 95% CI 0.15 to 0.19), the difference being markedly less for UK born women. UK born Pakistani women were more likely, and South Asian born less likely, to be educated post 16 than White British women. Smoking was uncommon among Pakistani women, though the difference comparing UK born Pakistani women to White British women was less than for other groups. BMI was lower among Pakistani compared to White British women (adjusted mean difference −1.12, 95% CI −1.43 to −0.81), the difference being greatest when partners were UK born irrespective of the woman’s place of birth. Pakistani women had higher fasting and postload glucose (mean difference 0.20 mmol/L, 95% CI 0.17 to 0.24; 0.37, 95% CI 0.28 to 0.45), higher fasting insulin and were more likely to have gestational diabetes (GDM).

Conclusions Our results suggest that some socioeconomic, lifestyle and pregnancy characteristics could be beginning to change in response to migration to the UK, with generally beneficial changes, that is, improving education and employment prospects, lower BMI and no evidence that being UK born has further increased the risk of GDM, but some negative, that is, slight increases in smoking.