Women who are obese when they conceive are more likely to have babies with birth defects than are mothers of normal weight, a US study suggests. (The study was published in the August issue of Archives of Pediatrics & Adolescent Medicine). Researchers interviewed 10,249 American women whose babies were born with birth defects between 1997 and 2002. The women were contacted between six weeks and two years after the baby's birth and asked their height and weight before pregnancy, along with other demographic and medical information. They were compared to 4065 women who had babies without birth defects during the same time period. For many types of birth defects, including spina bifida, heart, limb and genital defects, mothers were between 1.3 and 2.1-fold more likely to have been obese.