Improved outcomes for very low birthweight infants: evidence from New Zealand national population based data.
OBJECTIVE
To compare the survival and short term morbidity of all New Zealand very low birthweight (VLBW) infants born in two epochs, 1986 and 1998-1999.


METHODS
All level III and level II neonatal intensive care units (NICUs) in New Zealand.


METHODS
In 1986, data were prospectively collected for a study of retinopathy of prematurity (ROP). In 1998-1999, prospective data were collected by the Australian and New Zealand Neonatal Network (ANZNN). Both cohorts included all VLBW infants born during the calendar year and admitted to a NICU. Data were collected from birth until discharge home or death.


RESULTS
More VLBW infants were admitted for care in 1998-1999 (n = 1084, 0.96% of livebirths) than in 1986 (n = 413, 0.78% of livebirths; p < 0.001), including a higher proportion of VLBW infants of < 1000 g birth weight (38% v 32% respectively; p < 0.05). Survival to discharge home increased from 81.8% in 1986 to 90.3% in 1998-1999 (p < 0.001). The 1998-1999 cohort had a higher proportion of infants born in a hospital with a level III NICU (87% v 72% in 1986; p < 0.001) and receiving antenatal corticosteroids (80% v 58% in 1986; p < 0.001). In 1998-1999, the incidence of several morbidities had decreased compared with 1986, including oxygen dependency at 28 days (29% v 39% respectively; p = 0.001) and at 36 weeks postmenstrual age (16% v 23%; p = 0.002), grade 1 intraventricular haemorrhage (IVH) (8% v 24%; p < 0.001), grade 2/3 IVH (5% v 11%; p < 0.001), and stage 3/4 ROP for infants < 1000 g (6% v 13%; p < 0.001).


CONCLUSIONS
The outlook for VLBW infants in New Zealand has improved since 1986.
Darlow
B A
BA
Department of Paediatrics, Christchurch School of Medicine, New Zealand. brian.darlow@chmeds.ac.nz
Cust
A E
AE
Donoghue
D A
DA
D002543:Cerebral Hemorrhage / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000401:mortality*; D019102:Infant, Very Low Birth Weight; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data; D007902:Length of Stay; D008297:Male; D009017:Morbidity / Q000639:trends; D009520:New Zealand / Q000453:epidemiology; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000706:statistics & numerical data; D012178:Retinopathy of Prematurity / Q000453:epidemiology; D016896:Treatment Outcome