Effect of maternal hypertension on neonatal neutropenia and risk of nosocomial infection.

Neonatal neutropenia occurs in approximately 50% of newborns delivered by women with pregnancy-induced hypertension. It is thought to be transient, independent of birth weight and gestational age, and unassociated with significant risks, including infection. It recently was suggested that neonatal neutropenia occurs primarily in smaller, younger neonates, is related to the severity of pregnancy-induced hypertension, and importantly, may be associated with an increased risk for nosocomial infection. We examined these points in a large inborn population in consecutive years, performing retrospective (n = 110, 1989) and prospective (n = 151, 1990) studies in low birth weight (less than or equal to 2200 g) neonates delivered by women with pregnancy-induced hypertension. Overall, 40% to 50% of neonates studied developed neonatal neutropenia, and they were younger and smaller (P less than .01) than non-neutropenic neonates. In the prospective study, neutropenic neonates were more likely to have mothers with severe pregnancy-induced hypertension (P less than .001), and the incidence of neonatal neutropenia was primarily among neonates less than 30 weeks of gestation and less than 1500 g birth weight, approximately 80% vs 35% to 45% in older, larger neonates or infants (P less than .001). Although nosocomial infection occurred more frequently among the group of neutropenic neonates in the prospective study (P less than .02), the incidence was similar to that in matched non-neutropenic controls delivered of normotensive women. Thrombocytopenia (less than 100,000/mm3) was not more frequent in neutropenic neonates.(ABSTRACT TRUNCATED AT 250 WORDS)