Objective: The fetal response to an adverse intrauterine environment - reflected in low birth weight - is thought to cause an increased risk for adult hypertension. A possible mechanism by which fetal adaptive responses contribute to hypertension is an adverse effect on endothelial function. Identifying individuals with endothelial dysfunction as early as possible may assist in understanding the inverse association between birth weight and hypertension. The present study aimed to identify determinants of endothelial vasodilatation in the first week of life.
Methods: One hundred and four term newborns were studied in the first week after birth with regard to maximum vasodilatation in response to acetylcholine (endothelium-dependent) and nitroprusside (endothelium-independent) in the vasculature of the forearm skin, by use of a laser-Doppler device and iontophoresis. Bivariable and multivariable linear regression with various familial, gestational and neonatal potential covariates were used for the analysis.
Results: In the bivariable analysis, maximum perfusion after administration of acetylcholine was positively associated with birth weight, length, head circumference and maternal education level, but negatively associated with maternal hypertension during pregnancy. In the multivariable analysis, head circumference [b = 11.9 perfusion units/z-score, P = 0.02] and hypertension during pregnancy (b = -25.3 perfusion units from nonhypertensive to hypertensive, P = 0.02) remained significantly associated. Maximum perfusion after administration of nitroprusside was not related to any of the anthropometric measures; it was, however, related to gestational age (b = -11.1 perfusion units/week, P = 0.009).
Conclusion: This study showed that body size, head circumference in particular, is positively associated with endothelial vasodilatation in newborns, whereas hypertension during pregnancy is inversely associated with endothelial vasodilatation.