They say the higher the body mass index a woman has, the higher the chance of a Caesarean section.
Babies of obese women are at risk of stillbirth, prematurity, macrosomia (large for gestational age), neural tube defects and higher rates of childhood obesity.
Says Dr. Gary Hankin, of the American College of Obstetricians and Gynecologists, "Everything we do in obstetrics is made more difficult and more complex by obesity - from using external monitors to performing surgery."
New guidelines urge doctors to discuss weight before a woman conceives.
Once a woman is pregnant, recommendations include mild exercise and forgetting about the myth of "eating for two."
According to the guidelines, women who are average weight before pregnancy should gain 25 to 35 pounds. But overweight women should gain only 15 to 25 pounds, and the obese just 15 pounds.
