OBJECTIVE To estimate whether normotensive women who were born small for gestational age have low plasma volume in adult life, which is associated with later chronic hypertension. METHODS In 280 normotensive women with a history of hypertension in pregnancy, we recorded recalled gestational age and weight at birth and measured plasma volume (I-human serum albumin indicator dilution method). To correct for possible confounders, we recorded recent obstetric history and measured in each individual all constituents of the metabolic syndrome (World Health Organization criteria), sex hormones (progesterone and estradiol), renal function, and cardiac performance at rest (echocardiography). We estimated daily activity level with a validated questionnaire (Short Questionnaire to Assess Health-enhancing physical activity). We studied the relation between women's own birth weight centile and her adult plasma volume (mL) and adjusted for the effects of confounding variables using multiple linear regression analysis. RESULTS Birth weight correlated positively with adult plasma volume (P<.001). Linear regression analysis demonstrated that each 10 centile change in birth weight is associated with an average change of 46.6 mL (95% confidence interval [CI] 30.8-62.3) in adult plasma volume. This association persisted after adjustment for confounding factors (current body surface area, mean arterial pressure, total vascular resistance, glomerular filtration rate, and a total 24 hours of sodium output). After adjustment, each 10 centile change in birth weight was associated with an average change of 32.1 mL (95% CI 19.6-44.6) in adult plasma volume. Birth centile contributes 14% to the variation in total adult plasma volume. CONCLUSIONS Impaired fetal growth is associated with low plasma volume in adult life. METHODS II.