New guidelines have been issued for pregnant women who are obese (BMI 30+) stating they should only gain 11 to 20lbs during the course of their pregnancy.

The old guidelines, developed in 1990, didn't take into account the difference between overweight women (BMI 25-30) and obese women (BMI 30+). But, due to a rise in obesity levels in the past two decades, health officials guided by the Institute of Medicine and the National Research Council, felt that the guidelines needed updating.

As the New York Times explains:

About 27 percent of women of childbearing age fall into this category, defined as obese because they have a body mass index of 30 or more (for example, 5 feet 5 inches and at least 180 pounds).

The guidelines for women who are not obese remain unchanged:

  • Underweight women (BMI under 18.5) should gain 28 to 40 pounds during pregnancy.
  • Healthy-weight women (BMI between 18.5 and 25) should gain 25 to 35 pounds.
  • Overweight women (BMI between 25 and 30) should gain 15 to 25 pounds.

Previously, obese women were simply given the same advice as overweight women.

Doctors and health experts often advise women who are trying to get pregnant to get to a healthy weight first. This is because being obese can make it more difficult to conceive, and can cause complications during pregnancy. (Being underweight is also dangerous.)

If you are pregnant and concerned about your weight, see your doctor for advice: don't try to diet on your own.