The findings come from the U.K. Avon study, which is following the health of nearly 14,000 children born from April 1991 through December 1992. The study, by University of Bristol researcher Abigail Fraser, PhD, and colleagues, focuses on more than 8,500 mother/child pairs for whom detailed data were available.
But regardless of a woman's pre-pregnancy weight, weight gain during pregnancy affected the child's weight -- and at age 9, the child's risk of having high body fat, low levels of good HDL cholesterol, a big waistline, high blood pressure, and other risk factors for heart disease.
Children's heart risk increased with any weight gain during the first 14 weeks of pregnancy, and with any weight gain over 1.1 pounds per week during weeks 14 to 36 of pregnancy. The more weight a woman gained during these times, the higher her child's heart risk.
Weight gain after week 36 of gestation was not linked to heart risk in a woman's offspring.
What's going on? Fraser and colleagues suggest that the reason why these kids already have a high heart risk by 9 years of age is their fat mass. But exactly why children tend to be fat if their mothers gain too much weight during pregnancy isn't clear.
One thing is clear, comments obstetrician/gynecologist Jennifer Wu, MD, of New York's Lenox Hill Hospital.
"In order to help ensure healthier futures for their children, women considering childbearing should try to achieve ideal body weight pre-pregnancy and to adhere to recommended weight-gain guidelines," Wu says in a statement released by the Lenox Hill press office. Wu was not involved in the Fraser study.
The Fraser study appears in the June 15 issue of Circulation, a journal of the American Heart Association.