Weight gain by gestational age in both black and white women delivered of normal-birth-weight and low-birth-weight infants.

Although adequate maternal weight gain during pregnancy is widely acknowledged as a desirable goal, a contemporary standard for weight gain over the entire period of gestation based on a low-risk U.S. population has not been available. Information about usual weight gain in early pregnancy was particularly lacking. In a study monitoring various aspects of prenatal care in women in a population-based case-control study of low birth weight, we collected information on weight gain at various gestational ages in the 281 women who had prenatal care and were delivered of infants at a prepaid health plan facility where standardized records were kept. In white women who were delivered of infants who weighed greater than or equal to 3000 gm, average weight gain was 5.3 pounds at 9 to 10 weeks' gestation, 10.5 pounds at 11 to 20 weeks, 24.2 pounds at 21 to 30 weeks, and 35.1 pounds at 31 to 40 weeks. Weight gain among black women delivered of infants who weighed greater than or equal to 3000 gm was 4.2 pounds at 9 to 10 weeks' gestation, 14.8 pounds at 11 to 20 weeks, 24.5 pounds at 21 to 30 weeks, and 33.9 pounds at 31 to 40 weeks. Weight gain was highly variable at all gestational ages in both black and white women. Weight gain in both black and white women delivered of infants with weights greater than or equal to 3000 gm was linear at a rate of about 0.66 pounds per week from 8 through 20 weeks' gestation and linear at a rate of 1.06 pounds per week after week 20.