The updated guidelines by the Institute of Medicine regarding gestational weight gain provide clinicians with a basis for practice. Health care providers who care for pregnant women should determine a woman's body mass index at the initial prenatal visit and counsel her regarding the benefits of appropriate weight gain, nutrition and exercise, and, especially, the need to limit excessive weight gain to achieve best pregnancy outcomes. Individualized care and clinical judgment are necessary in the management of the overweight or obese woman who is gaining (or wishes to gain) less weight than recommended but has an appropriately growing fetus.