If you were overweight during your first pregnancy, odds are that you delivered a larger-than-average baby. So, you may reason, if you’re svelte for your second pregnancy, baby number two will be of average size. Not so, say authors of a study published in the American Journal of Obstetrics and Gynecology. Experts studied data on more than 146,000 women who’d given birth twice and found that women who maintained a normal body weight had the lowest risk of delivering abnormally large babies. But overweight women who lost pounds before their second pregnancies lowered—but didn’t eliminate—their risk of delivering big babies. Larger-than-normal babies are at risk of birth trauma and often require delivery by cesarean section.