Having Small Baby May Raise Mother's Heart Risks A full-term pregnancy with a small baby may cause changes in a woman's cardiovascular system that increase her risk for heart disease later in life, new data suggest. Using a nationally representative sample, researchers studied 6,608 women who had delivered full-term babies, 309 of them under the threshold weight, 5 pounds 8 ounces. Women who had had small babies were at about twice the risk for heart disease as those who had not, the researchers found. The study, published in the March issue of PLoS One, adjusted for age, diet, physical activity, hypertension, stroke, diabetes, family history and other known risks, but the association persisted. Diabetes and high blood pressure raise the risk of heart disease to about the same degree, said Dr. Radek Bukowski, lead author of the study and a professor of obstetrics and gynecology at the University of Texas Medical Branch in Galveston. "We thought for a long time that there was a common cause for heart disease and having a small baby," he said. But this study found that the association is independent of the traditional risk factors. The study could not explain the cause, but Dr. Bukowski said one possible factor was that delivery of small babies is associated with a reduction in placental hormones that stimulate blood vessel repair.