Weight Gain, Pregnancy Age and Breast Cancer Risk

Adult body weight can change a lot after we finish growing up. When women gain a lot of weight, the chance that they will develop breast cancer after menopause goes up. On the other hand, having a first pregnancy at a younger age seems to lower that risk. Researchers followed 48, 417 women from the UK over more than six years. They looked at two things: how much weight a woman had gained since adulthood and when she had her first child. They wanted to see if these two factors worked together to affect cancer risk.The study found that women who had a first pregnancy after age 30 and who gained more than thirty percent of their adult weight were at the highest risk. Even moderate weight gain – five to fifteen percent – increased danger for those who had a late first pregnancy. Women who never had children also faced higher risk, but their weight gain did not add extra danger. Women who kept a stable weight and had an early first pregnancy had the lowest risk. Still, gaining weight remained a danger regardless of when or whether they had children. The results suggest that women who gain lots of weight and have a late or no first pregnancy could be targeted for special programs that help them manage their weight to lower cancer risk.