Introduction: This study assesses the trends and predictors of mortality and morbidity in infants of gestational age (GA) <27 weeks from 1990 to 2007.
Materials and methods: This is a retrospective cross-sectional cohort study of infant deliveries between 1990 and 2007 in the largest perinatal centre in Singapore. This is a study of infants born at <27 weeks in 2 Epochs (Epoch 1 (E1):1990 to 1998, Epoch 2 (E2):1999 to 2007) using logistic regression models to identify factors associated with mortality and composite morbidity. The main outcomes that were measured were the trends and predictors of mortality and morbidity.
Results: Four hundred and eight out of 615 (66.3%) live born infants at 22 to 26 weeks survived to discharge. Survival improved with increasing GA from 22% (13/59) at 23 weeks to 87% (192/221) at 26 weeks (P <0.01). Survival rates were not different between E1 and E2, (61.5% vs 68.8%). In logistic regression analysis, higher survival was independently associated with increasing GA and birthweight, while airleaks, severe intraventricular haemorrhage (IVH) and necrotizing enterocolitis (NEC) contributed to increased mortality. Rates of major neonatal morbidities were bronchopulmonary dysplasia (BPD) (45%), sepsis (35%), severe retinopathy of prematurity (ROP) (31%), severe IVH/ periventricular leucomalacie (PVL) (19%) and NEC (10%). Although composite morbidity comprising any of the above was not significantly different between the 2 Epochs (75% vs 73%) a decreasing trend was seen with increasing GA (P <0.001). Composite morbidity/ mortality was significantly lower at 26 weeks (58%) compared to earlier gestations (P <0.001, OR 0.37, 95% CI, 0.28 to 0.48) and independently associated with decreasing GA and birth weight, male sex, hypotension, presence of patent ductus arteriosus (PDA) and airleaks.
Conclusion: Increasing survival and decreasing composite morbidity was seen with each increasing week in gestation with marked improvement seen at 26 weeks. Current data enables perinatal care decisions and parental counselling.