Maternal height, pregnancy weight gain, and birthweight

The Institute of Medicine recommends that short women gain less weight duri ng pregnancy than taller women in order to reduce the risk of high birthwei ght, which can lead to feto-pelvic disproportion. This recommendation, howe ver, is based on clinical judgment rather than on epidemiologic evidence, a s few studies have examined the relationships between maternal height, preg nancy weight gain, and infant birthweight. Our objective was to determine w hether maternal height is an independent risk factor for infant birthweight and to assess whether maternal height modifies the effect of pregnancy wei ght gain on infant birthweight. We examined the relationship between matern al height and infant birthweight in a multiethnic cohort of 8,870 women wit h uncomplicated pregnancies who delivered singleton infants at the Universi ty of California, San Francisco, 1980-1990. Using multiple linear regressio n, we modeled the contribution of height and weight gain to birthweight in four different ethnic groups. Increasing maternal height was significantly and positively associated with infant birthweight in White, Black, and Asia n women, but not Hispanic women. The relationship between pregnancy weight gain and infant birthweight was not modified by maternal height. (C) 2000 W iley-Liss, Inc.