Antenatal and postnatal risk factors for neonatal hypertension and infant follow-up.

Neonatal hypertension is an uncommon but important complication of intensive care management. The aims of this study were to identify in neonates with hypertension: antenatal and postnatal risk factors; aldosterone and renin levels; and report on outcome in early infancy. The study involved a retrospective review of neonates diagnosed with systemic hypertension from January 2001 to December 2005. Demographic data, risk factors, laboratory investigation, and follow-up data at 3-6 months of age were collected. Of the 2,572 newborn infants included, 34 (1.3%) had neonatal hypertension. Gestational age and birth weight and length were significantly lower in infants with hypertension. The median postnatal age at diagnosis of systemic hypertension was 5.0 days. Antenatal steroid administration, maternal hypertension, umbilical arterial catheter, postnatal acute renal failure, patent ductus arteriosus, indomethacin treatment and chronic lung disease were associated with the development of neonatal hypertension [odds ratios (OR) 8.7, 3.8, 10.0, 51.8, 5.9, 5.7 and 7.7, respectively]. Elevated aldosterone and renin levels occurred in 60% and 33% but had normalised in the majority by 6 months of age. The majority of infants do not require treatment for hypertension by 6 months of age.