Mortality and morbidity of neonates born at <26 weeks of gestation between 1998 and 2003

Advances in perinatal care have improved the survival of extremely premature infants, i.e. those of a gestational age (GA) <26 completed weeks. Perinatal counseling and decision-making should be based on contemporary mortality and morbidity information on an appropriate population. However, published reports are in large part based on data obtained during the mid 1990s. Moreover, several reports derive from tertiary care centers, thus presenting data obtained from selected groups of patients. Moreover, some studies describe outcomes by birth weight and not by GA, even if decisions regarding obstetric interventions and neonatal resuscitation are based on GA.
On these bases, a German group conducted a population-based study to evaluate the mortality in infants born < 26 completed weeks of GA between 1998 and 2003 in the Federal State of Hesse, and to describe pre- and postnatal risk factors for death in this population. Another goal of this study was to describe the frequencies of specific major complications of prematurity, such as bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), and retinopathy of prematurity (ROP), which may be relevant for further developmental outcome and quality of life.
Results show that 572 infants were liveborn, out of a total of 800 births. Among those admitted for neonatal intensive care, 62.3% survived until day 28. Among the neonates followed until death or discharge, 59.6% were discharged home. Statistical analysis showed that some variables are associated with an increased risk of death: twins (Odds Ratio (OR) 3.7; 95% Confidence Interval (CI) 1.34-10.26), multiple birth (=3 babies) [OR 8.14; CI 1.23-53.86], IVH =grade III (OR 4.79; CI 1.89-12.14), clinical risk index for babies score >15 (OR 2.9; CI 1.09-7.76), and a gestational age =23 weeks (OR 5.34; CI 1.24-22.98). Among infants discharged home, BPD was diagnosed in 52.2% of cases, IVH =grade III and/or PVL in 15%, and severe ROP in 29.8%. Among survivors to discharge home,  only 32% were free from major morbidities (BPD, IVH =grade III, and severe ROP).
These data, together with previously published studies, show a high mortality and a very frequent incidence of serious complications in surviving infants born at the limits of viability. Moreover, this population often experience developmental delay even in the absence of severe complications such as BPD, severe IVH, PVL, or ROP.
Interestingly, the results of this study show a lower incidence of IVH when compared to previous data, suggesting an overall improvement in neonatal care in the last decade. However, this finding must be confirmed in other cohorts before a trend of lower IVH rates can be generally assumed. In addition to further studies investigating mortality and morbidity in contemporary cohorts, long-term follow-up is urgently needed. Additional strategies should be developed in order to further increase intact survival.

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