• Vol. 42 No. 7, 328–337
  • 15 July 2013

Borderline Viability—Neonatal Outcomes of Infants in Singapore over a Period of 18 Years (1990 – 2007)



Download PDF


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 signifi ntly 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.

Advances in perinatal and neonatal care have resulted in the increased survival of extremely preterm infants in the nineties. As limits of viability continue to be lowered,
it is important to evaluate any further improvement in the new millennium. Accurate data on the probability of survival and the outcome of surviving infants are critical in developing appropriate perinatal guidelines and in counselling parents regarding treatment options available. Most recent survival data, and early morbidity and childhood outcomes based on accurate gestational age (GA) are required to make sound decisions regarding care of the high-risk mother and newborn. There is however limited information reported from perinatal centres in Asia.

This article is available only as a PDF. Please click on “Download PDF” on top to view the full article.