To examine the low birth weight - high blood pressure concept, the investigators conducted a prospective study on a cohort of children who were well characterized at birth. In 1988, data on weight, length, BP, gestation and maternal health were obtained on 1,160 newborn cases representing a range of birth weight and gestational age. They re-examined these children at age 11-13 years to test the overall hypothesis that birth weight, as well as other newborn measures of intrauterine growth, did not correlate with BP at age 11-13 years. The aims of the project were to: 1) determine if birth weight contributed to BP and/or body size in childhood; 2) determine if the duration of intrauterine growth in terms of gestational age contributed to BP and body size; 3) determine if newborn ponderal index, a measure of relative fetal growth, contributed to BP and body size; and 4) determine the relative contribution of newborn measures of birth weight, gestational age, BP, ponderal index, and maternal health to BP and body size in late childhood.