Central Apnea of Prematurity: Does Sex Matter?

Objective: Apnea is common among infants in the neonatal intensive care unit (NICU). Our group previously developed an automated algorithm to quantitate central apneas with associated bradycardia and desaturation (ABDs). Sex differences in lung disease are well described in preterm infants, but the influence of sex on apnea has not been established.

Study design: This study includes infants < 34 weeks' gestation admitted to the University of Virginia NICU from 2009 to 2014 with at least 1 day of bedside monitor data available when not on mechanical ventilation. Waveform and vital sign data were analyzed using a validated algorithm to detect ABD events of low variance in chest impedance signal lasting at least 10 seconds with associated drop in heart rate to < 100 beats/minute and drop in oxygen saturation to < 80%. Male and female infants were compared for prevalence of at least one ABD event during the NICU stay, treatment with caffeine, occurrence of ABDs at each week of postmenstrual age, and number of events per day.

Results: Of 926 infants studied (median gestational age 30 weeks, 53% male), median days of data analyzed were 19 and 22 for males and females, respectively. There was no sex difference in prevalence of at least one ABD event during the NICU stay (males 62%, females 64%, p = 0.47) or in the percentage of infants treated with caffeine (males 64%, females 67%, p = 0.40). Cumulative prevalence of ABDs from postmenstrual ages 24 to 36 weeks was comparable between sexes. Males had 18% more ABDs per day of data, but this difference was not statistically significant (p = 0.16).

Conclusion: In this large cohort of infants < 34 weeks' gestation, we did not detect a sex difference in prevalence of central ABD events. There was a nonsignificant trend toward a greater number of ABDs per day in male infants.

Key points: · Central apnea is pervasive among preterm infants in the NICU, but potential disparities between males and females have not been thoroughly studied.. · Identification of risk factors for central apnea can lead to improved treatment protocols.. · The rate and prevalence of central apnea events accompanied by bradycardia and desaturation does not significantly differ between male and female preterm infants..