Association between maternal weight gain and outcome of pregnancy

Weight gain during pregnancy may be viewed as a rough indicator of nutritional status. Numerous studies have shown a strong association between weight gain and pregnancy outcome, but none have been national in scope. The present study investigates this association using information from the 1980 National Natality and Fetal Mortality Surveys conducted by the National Center for Health Statistics. In 1980, one of five white mothers and one of four black mothers whose pregnancy lasted 40 weeks or longer gained less than 21 lb (9.5 kg). A minimal weight gain is more likely for mothers with a high prepregnancy weight, a fourth or higher order birth, low educational attainment or family income, who are black, unmarried, 35 years of age or older, or who smoke during pregnancy. When differences in mother's age, education, smoking practices, live birth order, sex of child, and period of gestation are taken into account, women gaining less than 21 lb (9.5 kg) are 2.3 times as likely to bear a low birth weight infant as are women with a higher weight gain. Likewise, a fetal death outcome is 1.5 times as likely for women gaining less than 21 lb (9.5 kg), even after controlling for these factors. Although current obstetric guidelines no longer advocate stringent weight control, it is evident that a significant proportion of pregnant mothers have a less than optimal weight gain, and are therefore at higher risk of an unfavorable pregnancy outcome.