A new study claims women who are obese before they become pregnant are more likely to have babies with birth defects.
Researchers looked at nearly 15,000 women and found the greatest risk was from spina bifida, although they also found abnormalities of the spine, heart, arms, legs, and abdomen increased.
The findings suggest that about 4% of women who are obese before pregnancy will have babies with major birth defects, versus 3% for healthy-weight women.
Morbidly obese women are also 60% more likely to have babies born with a rare abdominal defect in which the organs protrude through the belly button.
They are also 40% more likely to have babies with heart defects, 36% more likely to have babies with shortened arms or legs, and at least 20% more likely to have babies with gastrointestinal deformities.
The findings are published in the Archives of Pediatrics & Adolescent Medicine.
Kim Waller, the study's lead author from the University of Texas, said: "Obese women should not be overly alarmed by these findings because their absolute risk of having a child with a birth defect is low, and the cause of the majority of birth defects is unknown."