Women who do not drink enough milk while they are pregnant may prevent their babies' growth in the womb, researchers suggest. The scientists which conducted the study compared the birth weights of babies born to mothers who drank a cup or more of milk a day during pregnancy with ones whose mothers did not and found that the babies of milk drinkers were heavier. These doctors from McGill University, Canada, showed that vitamin D may be an important regulator for fetal growth. The study looked at 300 pregnant women who filled out questionnaires about their diet and lifestyle, also being asked information about how much milk they consumed and the dietary supplements taken. These women were non-smokers and followed conventional health advice during pregnancy. Vitamin D, contained by milk, is considered important in skeletal growth and in producing strong bones and is needed by women to transport calcium to the fetus. For every extra 250ml of milk drunk a day, there was an increase of 41g in birth weight. "This is an interesting study and very topical as there is a lot of interest in this area. In Canada, milk is fortified, and a lot of the vitamin D intake seems to come from this source. In other countries, sunlight or supplements are the main source as it is not found in common foods, but there is a lot of dispute between scientists as to how much is the optimal amount to take a day," stated Dr Gail Goldberg, a nutritionist from Human Nutrition Research Centre, Cambridge, UK.