Female babies who are above average in weight and length are at an increased risk for breast cancer as adults, a study finds.
Although previous research has been inconclusive, a study published in this week's Public Library of Science journal PLoS Medicine finds there is strong evidence between birth length, weight and breast cancer.
Isabel dos Santos Silva of the London School of Hygiene and Tropical Medicine and colleagues examined 32 studies involving a total of 600,000 women -- 22,000 of whom had breast cancer -- living in mostly developed countries throughout the world.
Babies with bigger heads also have a slightly greater risk of breast cancer as adults, researchers said.
Women who weighed 8.8 pounds or greater at birth had a 12 percent higher risk of breast cancer than babies who weighed between 6.6 and 7.7 pounds at birth, according to the study. Researchers believe birth length and weight may play a role in up to 5 percent of all cases of breast cancer.