Treatment-by-gender effect when aiming to avoid hyperoxia in preterm infants in the NICU

Objective: To examine gender-specific differences in response to the O-2 saturation (SpO(2)) targets aimed at avoiding hyperoxia in very low birth weight infants (VLBW). Methods: Analysis of a prospectively collected database of all infants <= 1250 g in two perinatal centres. A change was instituted in January 2003 with the objective of avoiding hyperoxia with target SpO(2) at 85-93% (period II). Prior to this, SpO(2) high alarms were set at 100% and low alarms at 92% (period 1; from January 2000 to December 2002). Results: Of the 497 infants that met enrolment criteria, 297 (60%) were born during period I and 140 (47%) of them were male. During period II, 200 infants were born and 101 (50%) were male. Analysis by gender showed that the rate of retinopathy of prematurity, bronchopulmonary dysplasia and length of stay is significantly better for female infants than males on period II compared to period I. Neither gender experienced increased short-term neurological morbidity in response to lower SpO(2) targets. Conclusions: There is a significant gender-specific difference favouring females in the beneficial effects produced by avoiding high SpO(2) and hyperoxia, with no difference in the distribution of any potential short-term detrimental effects.