Elsevier

Early Human Development

Volume 90, Issue 12, December 2014, Pages 821-827
Early Human Development

Population-based trends in mortality and neonatal morbidities among singleton, very preterm, very low birth weight infants over 16 years,☆☆

https://doi.org/10.1016/j.earlhumdev.2014.08.009Get rights and content

Highlights

  • Mortality and combined outcomes of death or major neurological morbidities decreased.

  • Survival without one or more major morbidity

  • Continuous monitoring of neonatal care to target therapeutic efforts

Abstract

Background

Improved survival of singleton very preterm, very low birth weight (VPTVLBW) infants has been associated with increasing rates of severe neonatal morbidities.

Aim

To assess changes in mortality and neonatal morbidities among singleton VPT-VLBW infants.

Study design

Population-based observational study of data collected by the Israel Neonatal Network.

Subjects

10,705 singleton VPT-VLBW infants born at 24–32 gestational weeks in 1995–2010.

Outcome measures

Mortality and major neonatal morbidities over 3 time periods: 1995–2000, 2001–2005, and 2006–2010. Major neurological morbidities comprised intraventricular hemorrhage grades 3–4, periventricular leukomalacia and retinopathy of prematurity grades 3–4.

Results

The mortality rate decreased over time from 20.2% to 13.8% for all birth weight and gestational age groups. Compared to the 1995–2000 period, the adjusted odds ratios (aORs) (95% confidence intervals,) for mortality in 2001–2005 and 2006–2010 were 0.78 (0.67–0.90) and 0.72 (0.62–0.84), respectively. The combined outcomes of death or major neurological morbidities, aOR 0.74 (0.65–0.84) and death or major neurological morbidities and/or bronchopulmonary dysplasia aOR 0.85 (0.75–0.96) decreased significantly between the first and last periods. A significant improvement in mortality rates and survival without one or more major neonatal morbidity was observed for all birth weight and gestational age groups.

Among 8,886 surviving infants the rates of major neurological morbidities decreased from 16.4% to 12.8%, aOR 0.80 (0.68–0.95).

Conclusion

The improving survival of singleton VTP-VLBW infants was not associated with a concomitant increase in the risk for major neonatal neurological morbidities among surviving infants. Bronchopulmonary dysplasia, however, remained a significant burden. This analysis emphasizes the need to direct efforts towards the prevention and treatment of adverse respiratory sequelae.

Introduction

Research efforts in perinatal and neonatal medicine over the last two decades have been directed at reducing the mortality and morbidity in very preterm, very low birth weight (VPT-VLBW) infants. They have been focused on improving medical care for pregnant women, identifying and reducing risk factors and improving perinatal care. It is generally accepted that neonatal survival rates have substantially increased, even in extremely preterm infants [1]. A high proportion of survivors however, experience neonatal morbidities which may be associated with adverse long-term outcomes [2], [3], [4], [5], [6], [7]. Population-based studies have recently reported varying trends for mortality and morbidity of VLBW infants [2], [3], [4], [5], [8], [9], [10]. Comparative studies have shown great variability in VLBW neonatal outcomes within the same geo-economical regions [6] and between different care systems of developed countries [11], [12].

We hypothesized that the improving survival of VPT-VLBW infants was not associated with an increased risk of major neurological or respiratory morbidity in the survivors. This study aimed to assess the trends in mortality and morbidity in a national cohort of singleton VPT-VLBW infants born in Israel between 1995 and 2010.

Section snippets

Data collection

This population-based observational study was based on the analysis of data collected by the Israel Neonatal Network on VLBW infants (≤ 1500 g) born in Israel between January 1995 and December 2010. Data were collected on all live births of infants with a birth weight of ≤ 1500 g. All 28 neonatal units in Israel, comprising the Israel national VLBW infant database, were included in data collection (see Appendix A). Data were recorded on a structured form which includes parental demographic

Perinatal and neonatal characteristics

The study population comprised 10,705 singleton VPT-VLBW infants born at 24–32 weeks' gestation over three time periods, 1995–2000 (n = 3,846 infants), 2001–2005 (n = 3,475 infants) and 2006–2010 (n = 3, 384 infants). The demographic and perinatal characteristics are shown in Table 1. There were significant increases over time in maternal age (p = 0.0001) and maternal education > 12 years (p < 0.0001), earlier initiation of antenatal care (≤ 12 weeks, p < 0.0001), infertility therapy (p = 0.0003), diabetes

Discussion

Progressively enhanced changes in perinatal and neonatal intensive care of preterm infants have led to an increase in survival along with changes in the rates of major neonatal morbidities, including brain injury, BPD, ROP, NEC and sepsis [2], [3], [4], [5], [6], [7], [8], [9], [10], [11]. These morbidities have influenced the rates of long term sequelae including cerebral palsy, visual acuity disorders and chronic respiratory problems. Several reports on the reduction of these serious

Disclaimer

All of the authors take responsibility for this study and proved this manuscript.

None of the authors has any conflicts of interest to declare.

No current external funding sources for this study was employed; ie for study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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  • Cited by (0)

    The Israel National Very Low Birth Weight Infant database is partially supported by the Israel Center for Disease Control and the Ministry of Health.

    ☆☆

    Disclaimer: No conflicts of interests are noted for any of the authors which may have impacted the reporting of the results of this study.

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