The Institute of Medicine , the nation’s most influential medical advisory group, has updated its guidelines for weight gain during pregnancy for the first time since 1990. The revised recommendations, released May 28, which also include the first advice regarding exercise during pregnancy, reflect new data on prenatal health as well as several recent shifts in the obstetric landscape — pregnant women in the U.S. are now older, more likely to deliver multiple births and ethnically more diverse than they were 20 or 30 years ago.
