Drinking three cups of tea a day during pregnancy increases the risk of having overweight children, according to a study of more than 50,000 mothers.

It found pregnant women who consumed more than 200mg a day of caffeine were more likely to have children that are overweight at preschool and school ages.

The study, which was carried out by researchers at Sahlgrenska Academy in Sweden in collaboration with the Norwegian Institute of Public Health, tracked the weight of children up to the age of eight and was one of the world’s largest health surveys of pregnant women.