During pregnancy, many women gain "substantially more than we would like," IOM committee chairwoman Kathleen Rasmussen, ScD, PhD, tells WebMD.
"It is important for women to gain within [the new guidelines] and if possible, it's important for women to begin pregnancy at a good weight," says Rasmussen, who is also a Cornell University nutrition professor.
New Pregnancy Weight Guidelines
Here are the guidelines for pregnancy weight gain, based on a woman's BMI (body mass index) before becoming pregnant with one baby:
Underweight: No weight gain guidelines are available because of insufficient data.
"For women to achieve these goals, they are going to need individualized attention before, during, and after pregnancy," with support from their doctors, families, and communities, Rasmussen says.
The IOM's new pregnancy weight gain guidelines are similar to its 1990 guidelines, except now there is an upper limit on how much weight obese women should gain while pregnant.
"The fact that the numbers are the same suggests that they have withstood the scrutiny that they've received in the last 19 years. So women can have confidence in these targets," Rasmussen says. She says that although the 1990 guidelines focused on infant health, the new guidelines also consider the mother's health.