Elsevier

Early Human Development

Volume 95, April 2016, Pages 5-8
Early Human Development

Improved survival and neurodevelopmental outcomes among extremely premature infants born near the limit of viability

https://doi.org/10.1016/j.earlhumdev.2016.01.015Get rights and content

Highlights

  • Death or neurodevelopmental impairment among surviving infants decreased among infants born 22 to 24 weeks of gestational age from 1998 to 2011.

  • Incidence of several major morbidities, including late-onset sepsis, surgical necrotizing enterocolitis, and bronchopulmonary dysplasia also declined.

Abstract

Background

Infants born near the limit of viability are at high risk for death or adverse neurodevelopmental outcomes. It is unclear whether these outcomes have improved over the past 15 years.

Aim

To determine if death and neurodevelopmental impairment have declined over the past 15 years in infants born at 22 to 24 weeks' gestation.

Subjects

We identified infants born at 22 to 24 weeks' gestation in our center in two epochs: 1998–2004 (Epoch 1) and 2005–2011 (Epoch 2).

Outcome measures

The primary outcome, death or neurodevelopmental impairment, was evaluated at 17–25 months' corrected gestational age with neurologic exams and Bayley Scales of Infant Development. Perinatal characteristics, major morbidities, and outcomes were compared between epochs.

Results

Birth weight and gestational age were similar between 170 infants in Epoch 1 and 187 infants in Epoch 2. Mortality was significantly lower in Epoch 2, 55% vs. 42% (p = 0.02). Among surviving infants, late-onset sepsis (p < 0.01), bronchopulmonary dysplasia (p < 0.01), and surgical necrotizing enterocolitis (p = 0.04) were less common in Epoch 2. Neurodevelopmental impairment among surviving infants declined from 68% in Epoch 1 to 47% in Epoch 2, p = 0.02. Odds of death or NDI were significantly lower in Epoch 2 vs. Epoch 1, OR = 0.31 (95% confidence interval; 0.16, 0.58).

Conclusion

Risk of death or neurodevelopmental impairment decreased over time in infants born at 22 to 24 weeks' gestation.

Introduction

Infants born near the limit of viability are at high risk for death or adverse neurodevelopmental outcomes [1], [2], [3], [4], [5]. Recent evidence suggests that survival has improved in this population over the past 20 years [5], [6], but there is little evidence that neurodevelopmental outcomes of surviving infants have changed. Two multicenter studies by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network reported that neurodevelopmental outcomes did not improve the over consecutive birth epochs in infants born 22–24 weeks' gestation between 1993 and 2004 [1], [4]. The most recent of these studies reported death in 67.6% of these infants in 2002–2004, and neurodevelopmental impairment (NDI) in 58.7% of survivors [4]. A recent study from Japan's Neonatal Research Network described better than previously reported outcomes in this group, with death or NDI seen in 80.0% of infants born at 22 weeks' gestation, 63.7% at 23 weeks' gestation, and 38.9% at 24 weeks' gestation [7]. Current knowledge of outcomes for infants born at these early gestational ages is critical for clinicians and families when making early obstetrical and neonatal care decisions [8].

The objective of this study was to compare death and early childhood neurodevelopmental outcomes for infants born < 25 weeks' gestation in our center between two recent birth epochs.

Section snippets

Study population

We identified all infants born 22 0/7–24 6/7 weeks' gestation that were admitted to the Neonatal Intensive Care Unit at Duke University Medical Center from January 1, 1998 to December 31, 2011. Infants admitted from an outside hospital at > 48 h of age were excluded. The study period was divided into two epochs. Epoch 1 included infants born from 1998 to 2004 and Epoch 2 included infants born from 2005 to 2011. Epoch 1 was chosen to overlap with the most recent NICHD Neonatal Research Network

Results

During the study period, a total of 357 infants were born at 22–24 weeks of gestation. Of these infants, 170 (48%) were born in Epoch 1 and 187 (52%) were born in Epoch 2. Epoch 1 and 2 infants did not differ significantly in birth weight, GA, inborn status, gender, multiple gestations, or receipt of antenatal steroids (Table 1). The proportion of infants born by cesarean delivery was higher in Epoch 2. Among surviving infants, incidence of severe IVH, periventricular leukomalacia,

Discussion

In our center, survival of infants born 22–24 weeks of GA has improved over the past 15 years. In fact, we observed decreased mortality as well as decreased NDI among survivors. When the cohort was divided by birth GA, we saw a decrease in NDI in infants born at 24 weeks of gestation, but no improvement in the outcomes among the infants born at 23 weeks of gestation. While these results are limited by the small number of surviving infants born at 23 weeks of gestation in our cohort, it suggests that

Conclusions

In our center, the incidence of death or NDI decreased over time in infants born 22–24 weeks of gestation. In particular, NDI significantly decreased in infants born at 24 weeks of gestation. While these results are encouraging, the rates of death or NDI remain very high and clinicians should continue to counsel parents of the significant risks at these early gestational ages. Further research is needed to identify and implement practices associated with improving the outcomes in this vulnerable

Conflicts of interest

The authors have no relevant conflicts of interest to disclose.

Acknowledgments

Dr. Younge received support from National Institutes of Health (5T32HD043728-10). Dr. Smith received support from the National Institutes of Health and the National Center for Advancing Translational Sciences (HHSN267200700051C, HHSN275201000003I and UL1TR001117); he also receives research support from industry for neonatal and pediatric drug development (www.dcri.duke.edu/research/coi.jsp). Dr. Cotten received support from National Institutes of Health (5U10 HD040492-10).

References (32)

  • N. Ishii et al.

    Outcomes of infants born at 22 and 23 weeks' gestation

    Pediatrics

    (2013)
  • T.N. Raju et al.

    Periviable birth: executive summary of a joint workshop by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal–Fetal Medicine, American Academy of Pediatrics, and American College of Obstetricians and Gynecologists

    J Perinatol

    (2014)
  • N. Bayley

    Bayley Scales of Infant Development

    (1993)
  • N. Bayley

    Bayley Scales of Infant Development

    (2006)
  • B.R. Vohr et al.

    Are outcomes of extremely preterm infants improving? Impact of Bayley assessment on outcomes

    J Pediatr

    (2012)
  • S. Jary et al.

    Comparison of Bayley-2 and Bayley-3 scores at 18 months in term infants following neonatal encephalopathy and therapeutic hypothermia

    Dev Med Child Neurol

    (2013)
  • Cited by (32)

    • Longitudinal medical needs for periviable NICU survivors

      2022, Early Human Development
      Citation Excerpt :

      NDI is typically defined as a composite of neurologic and sensory impairments, including cerebral palsy, severe visual impairment, severe hearing impairment, and/or delays in cognitive, language, or motor development. Incrementally assessed NDI is frequently used as the proxy measurement for long-term outcomes in neonatology to assess specific demographic cohorts, compare experimental and control groups, and to inform counseling of families in the antepartum period and in the Neonatal Intensive Care Unit (NICU) [1–6,8–10]. However, NDI alone provides an incomplete depiction of the impact a periviable birth may have on the life of an infant, his or her caregivers, and his or her family [8–12].

    • Systematic review of tube-fed preterm infants in the home supported within a family-centered program

      2018, Journal of Neonatal Nursing
      Citation Excerpt :

      Feedback from families who have delivered home enteral feeding is generally positive (Bissell and Miall, 2009), with Dixon et al. (2011) citing benefits in terms of improved family attachments, normalization of the family unit, increased breastfeeding success, reduced infection risk, and significant healthcare cost savings. Survival rates and outcomes of the smallest and most vulnerable infants continue to improve (Younge et al., 2016), with their clinical care requiring expensive high-level technology and prolonged hospitalization (Petrou et al., 2009). Neonatal services must be geared towards providing intensive care but this level of care is required for only a tiny proportion of infants.

    • Neurodevelopmental considerations in surgical necrotizing enterocolitis

      2018, Seminars in Pediatric Surgery
      Citation Excerpt :

      The precise underlying mechanism of improved neurodevelopmental outcomes remains unclear and is likely multifactorial, but the goal of better outcomes has been realized in several studies by mitigating known, contributing factors. Yonge et al.5 identified a significant decrease in NDI rates from 68% to 47%, paralleling significant decreases in the proportion of infants with late-onset sepsis, surgical NEC, receipt of postnatal dexamethasone, and BPD, each of which has been associated with adverse neurodevelopmental outcomes. The authors point to a number of quality improvement (QI) efforts and practice changes over time that contributed to those improvements.

    • Low birth weight babies and disability

      2024, Low Birth Weight Babies and Disability
    View all citing articles on Scopus
    View full text