Birth size, growth, and blood pressure between the ages of 7 and 26 years: failure to support the fetal origins hypothesis.

The "fetal origins hypothesis" asserts that birth weight is inversely related to later blood pressure. Data from a cohort of 891 infants born in Dunedin, New Zealand, in 1972-1973 whose blood pressure was measured at 2-year intervals from age 7 years to age 15 years and at ages 18 and 26 years were used to test this hypothesis. Three regression models based on standardized scores for weight and height were used. The first showed that at any of the ages at which the cohort was assessed, an increase in birth weight of one z score (one standard deviation) was commensurate with a decrease of 0.29 mmHg (95% confidence interval: -0.17, 0.76) in blood pressure. The second model showed that a one-z-score increase in weight between birth and a subsequent age was associated with an increase in systolic blood pressure of 0.96 mmHg (95% confidence interval: 0.53, 1.38). This estimate applied to all ages. The third model showed that the effect of an interaction between birth weight and later weight was not significant; thus, there was no evidence to suggest that children with a low birth weight who became overweight or obese had extra high blood pressure. Similar results were obtained for height. These results fail to support the fetal origins hypothesis.