Effects of maternal hypertension in very-low-birth-weight infants

C. R. Kim, B. R. Vohr and W. Oh
Hanyang University School of Medicine, Seoul, Korea.

OBJECTIVE: To determine the effects of mild vs severe maternal hypertension on the neonatal morbidity of very-low-birth-weight infants. DESIGN: Cohort case-control study. SETTING: Tertiary care center neonatal intensive care unit. PATIENTS: Thirty-nine infants born to mothers with maternal hypertension (blood pressure > or = 140/90 mm Hg on 2 occasions during pregnancy) among 267 very-low-birth-weight infants (< or = 1250 g) admitted to the special care nursery between January 1, 1991, and December 31, 1992. Each infant was matched for gestational age and survival to 2 control infants born to normotensive mothers. The cohort included 11 infants of mothers with mild hypertension, 28 with severe hypertension, and 78 controls. MAIN OUTCOME MEASURES: Late and variable decelerations, incidence of small size for gestational age, respiratory distress syndrome, intraventricular hemorrhage, patent ductus arteriosus, apnea, ventilator therapy, oxygen requirement, and bronchopulmonary dysplasia. RESULTS: The mild and severe maternal hypertension groups had significantly lower birth weights and more infants small for gestational age than did controls. The incidence of respiratory distress syndrome, however, was significantly lower in infants of mothers with mild hypertension than in those with mothers with severe hypertension. Those in the mild group had fever days of ventilatory therapy and lower oxygen requirements than both the infants in the severe group and control infants. The incidence of apnea in the mild hypertension group was significantly lower than that in the severe hypertension group. CONCLUSIONS: Although mothers with both mild and severe hypertension have an increased incidence of infants small for gestational age, the infants born to mothers with mild hypertension had less respiratory distress syndrome, apnea, ventilator therapy, oxygen requirements, and bronchopulmonary dysplasia when compared with very-low-birth-weight infants born to mothers with severe hypertension.