“Eating for two? New guidelines are setting how much weight women should gain during pregnancy -- surprisingly little if they're already overweight. The most important message: Get to a healthy weight before you conceive, says the Institute of Medicine in the first national recommendations on pregnancy weight since 1990. It's healthiest for the mother -- less chance of pregnancy-related high blood pressure or diabetes, or the need for a C-section -- and it's best for the baby, too. Babies born to overweight mothers have a greater risk of premature birth or of later becoming overweight themselves, among other concerns. Meeting the guidelines could be a tall order, considering that about 55 percent of women of childbearing age are overweight, that preconception care isn't that common and about half of pregnancies are unplanned. What if a mom-to-be has gained too much? On average, overweight and obese women already are gaining five more pounds than the upper limit."