Abnormal circadian blood pressure regulation in children born preterm.

OBJECTIVE

To assess a possible relationship between prematurity and casual blood pressure (BP) by means of 24-hour ambulatory BP monitoring (ABPM).

STUDY DESIGN

ABPM was performed in 41 children aged 5 to 17 years who were born prematurely with (n = 11) or without intrauterine growth restriction, and in 27 matched children who were born at term with a birth weight appropriate for gestational age.

RESULTS

Although BP did not differ between the preterm group and control subjects during the daytime, nocturnal standardized systolic BP was elevated (P < .05) and a lack of nocturnal decrease was more prevalent in the preterm children compared with the control subjects (73% versus 41%, P = .01). The difference was caused by a marked increase of nighttime systolic BP in the light-for-date children (1.17 +/- 0.61 standard deviation scores; P < .01), although preterm children with appropriate weight (0.33 +/- 1.00) were not different from control subjects (0.09 +/- 0.73). Nighttime BP standard deviation scores were closely correlated with standardized heart rate, compatible with a role of sympathetic hyperactivation.

CONCLUSION

Subtle abnormalities of BP regulation, indicated by a selective increase of nocturnal systolic BP, are present during childhood in subjects born prematurely, and are prominent in those with intrauterine growth restriction.