Pregnant women who smoke risk delivering a premature or low-birthweight baby with serious health and learning problems. But the early damage done to a baby’s circulatory system may persist into adulthood, leading to heart disease and stroke years later, according to findings presented at a recent American Heart Association conference. Researchers collected data on more than 700 people born between 1970 and 1973. By age 30, the adult children of the 215 mothers who smoked during pregnancy had thicker carotid artery walls—an early sign of atherosclerosis—than did the adults whose moms didn’t smoke. The study suggests artery disease may begin during gestation, adding yet another reason for moms-to-be to kick the habit for good.