Objective To study the prevalence and severity of BPD in infants with a high rate of prenatal steroid (86%) and surfactant (84%) treatment.
Methods BPD was analyzed in a national cohort of 462 infants with gestational age (GA) of 22 to 27 completed weeks (wks) or birth weight (BW) of 500 to 999 g born in Norway in 1999 and 2000. BPD was classified as mild BPD; ventilatory support and/or oxygen at 28 days, moderate BPD; oxygen at 36 wks, and severe BPD; ventilatory support at 36 wks. 77 infants died before 28 days. Five infants who died after 28 days but were ventilated since birth were also classified with severe BPD.
Results No infant with GA 22–25 wks survived without a diagnosis of BPD. Moderate or severe BPD was seen in 80% of infants with GA 22–23 wks, 75% in GA 24 wks and 59% in GA 25 wks. Overall, moderate or severe BPD was significantly more often seen in boys (51%) than in girls (36%) (p = 0.001). This sex difference also remained in infants with GA 26–28 wks, (girls 29%, boys 46%, p = 0.005). However, for infants with GA 22–25 wks no such difference in moderate or severe BPD was seen (girls 64%, boys 71%, p = 0.456).
Conclusions BPD remains a severe problem in extremely premature infants in spite of prenatal steroids and surfactant treatment. Although BPD overall is more commonly seen in boys than in girls, for GA 22–25 wks boys and girls are equally affected.