PERINATAL OUTCOMES OF A LARGE COHORT OF EXTREMELY LOW GESTATIONAL-AGEINFANTS (23 TO 28 COMPLETED WEEKS OF GESTATION)

Objectives: To determine gestational age (GA)-specific mortality rates ; the effects of GA, birth weight, sex, and multiple gestation on mort ality rates; short-term morbidity for infants born at 23 to 28 weeks G A; and impairment rates at a corrected chronologic age of 18 months fo r those born at 23 to 25 weeks GA, Methods: A data base analysis was p erformed with a linked obstetric and a neonatal database, GA was deter mined by obstetric data and confirmed by early ultrasonography (availa ble in 88%) on all births <30 weeks GA at British Columbia's tertiary perinatal center from 1983 to 1989. Results: Of 1024 births occurring between 23 and 28 weeks GA, 911 were live born, The mortality rate dec reased with increasing GA: 84% at 23 weeks; 57% at 24 weeks; 45% at 25 weeks; 37% at 26 weeks; 23% at 27 weeks; and 13% at 28 weeks GA, For each GA,mortality rate versus birth weight plots showed a decreasing m ortality rate with increasing birth weight, except for infants who wer e large for GA, Male infants had a higher mortality rate than female i nfants (odds ratio, 1.8; confidence interval, 1.4 to 2.5). Twins fared worse than singletons with a decreasing effect from 24 weeks GA (odds ratio, 10.3) to no effect at 28 weeks GA, The median number of days s upported by mechanical ventilation and the length of stay in the neona tal intensive care unit decreased markedly with increasing GA, Eightee n-month outcome of survivors between 23 and 25 weeks GA with 93% follo w-up rate revealed an overall impairment rate of 36%, but 6 of the 9 s urviving 23-week infants had major impairments. Conclusions: The GA-sp ecific perinatal outcome results of this large cohort provide informat ion to assist in perinatal management decision making and for counseli ng parents prenatally.