Researchers led by Katherine Stothard at Newcastle University in Great Britain found that the range of dangers for obese women is wider than previously thought. Moreover they are even greater for pregnant women and particularly for their developing babies. A new analysis, published February 11 in the Journal of the American Medical Association, documents a wider than expected range of birth defects that are more likely to plague babies born to obese women.

It appears that babies born to obese mothers are more likely to have serious birth defects. "We found that being obese in pregnancy can increase a woman's risk of having a range of birth defects," said study senior author Judith Rankin, a reader in maternal and perinatal epidemiology at Newcastle University in Newcastle upon Tyne, United Kingdom.

Rankin's team undertook the study because of the growing problem of obesity in women of childbearing age. In the U.S., one-third of women 15 and older are obese, the authors note, and those numbers are expected to rise. The definitions of overweight and obese differed somewhat from study to study, but many studies used those set by the World HealthOrganization which say that a body mass index or BMI of 25 and above for overweight and 30 and above for obese.

The study’s advice was that leading clinicians said the government should be focusing anti-obesity campaigns on women of child-bearing age. It is well known that women who are obese are more likely to have difficulty conceiving and once they are pregnant, overweight and obese women and their babies are at a greater risk of a range of health problems in general.