We examined whether the risk of stillbirth was related to ambient air pollution in a UK population. Prospective case–control study.

Forty-one maternity units in the UK.

Women who had a stillbirth ≥28 weeks’ gestation (n = 238) and women with an ongoing pregnancy at the time of interview (n = 597).

Secondary analysis of data from the Midlands and North of England Stillbirth case–control study only including participants domiciled within 20 km of fixed air pollution monitoring stations.

Pollution exposure was calculated using pollution climate modelling data for NO2, NOx and PM2.5.

The association between air pollution exposure and stillbirth risk was assessed using multivariable logistic regression adjusting for household income, maternal body mass index (BMI), maternal smoking, Index of Multiple Deprivation quintile and household smoking and parity.