A ground-breaking study to discover how much air pollution and water contamination can affect a baby's growth in the womb is starting in Bradford.

It aims to assess the exposure of pregnant women to air pollution and chemicals in tap water and will be carried out for three weeks from Monday by researchers at the Born in Bradford project and Imperial College, London.

Born in Bradford is one of the world's biggest studies into children's health and is tracking the lives of 10,000 babies born at Bradford Royal Infirmary.

It aims to find out why babies born in Bradford are 30 per cent more likely to be underweight at birth, twice as likely to die in their first year, three times as likely to have diabetes and four times more likely to be disabled than babies born in other parts of the UK.

This part of the research is funded by the Natural Environment Research Council, the Economic and Social Research Council and the European Commission Health Impacts of Long-Term Exposure to Disinfection By-Products in Drinking Water (HiWATE) project.

Mothers-to-be will be asked to fill in a diary recording their daily activities, travel and water use.

Levels of air pollution, and of chemicals in tap water, will be measured at each mother's home. This will allow researchers to estimate what level of chemicals pregnant mothers are exposed to.

The information will be used in a study on the effects of air pollution and water contamination on the birth weight of babies in the Born in Bradford study.

Ultimately, this research will improve understanding of the effects of air pollution and disinfection by-products on babies' growth in uterus.

Pauline Raynor, Born in Bradford programme manager, said: "It's important to do this research, because we are all are exposed to tap water, through drinking, eating and washing and we all breathe in the air around us, therefore we may all be exposed to the chemicals that exist in water and air. Previous studies have shown that these may affect the birth weight of babies but the evidence is not conclusive.

"With so many people potentially at risk from these chemicals, it is very important that we investigate any possible health effects that they may have.

"In particular, it is important to investigate any potential risk factor to babies' growth and development, because we know that low birth-weight is associated with poorer health in later life. If we can learn what factors contribute to low birth-weight then we can improve a baby's chance of a healthy start to life."

A group of 50 pregnant women who attend the antenatal clinic at Bradford Royal Infirmary will be recruited by researchers. Any mothers who would like to help support this project should contact the project on (01274) 364474.