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Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale
Published on: August 25, 2014
Temporal Trends in Neurodevelopmental Outcomes to 2 Years After Extremely Preterm Birth
Jeanie L Y Cheong1,2,3, Joy E Olsen1,2, Katherine J Lee4,5
1Neonatal Services, Royal Women's Hospital, Melbourne, Australia.
Insights
Survival rates for extremely preterm infants have improved significantly since the 1990s. Importantly, this increased survival has not led to a rise in major neurodevelopmental disabilities at two years corrected age.
Area of Science:
- Neonatalogy
- Developmental Pediatrics
- Public Health
Background:
- Infant survival rates for extremely preterm (EP) infants (<28 weeks' gestation) have risen since the early 1990s.
- It is crucial to ascertain if this improved survival correlates with an increase in neurodevelopmental disabilities.
Purpose of the Study:
- To evaluate changes in major neurodevelopmental disability and survival free of major neurodevelopmental disability at 2 years corrected age in EP infants.
- To compare outcomes across different eras of EP births.
Main Methods:
- Analysis of four prospective longitudinal cohort studies of EP live births (22-27 weeks' gestation) in Victoria, Australia.
- Data from 1152 children across four eras (1991-1992, 1997, 2005, 2016-2017) were analyzed for 2-year outcomes.
- Outcomes included survival, blindness, deafness, cerebral palsy, and developmental delay, with major neurodevelopmental disability defined as blindness, deafness, moderate-to-severe cerebral palsy, or a developmental quotient < -2 SDs.
Main Results:
- Survival to 2 years increased from 53% in 1991-1992 to 73% in 2016-2017.
- Rates of cerebral palsy decreased in the most recent cohort (6% in 2016-2017 vs. 10-12% previously).
- Survival free of major neurodevelopmental disability steadily increased over time, reaching 62% in 2016-2017 (OR 1.30 per decade).
Conclusions:
- Survival free of major disability in extremely preterm infants has improved by 20% since the early 1990s.
- Increased survival among EP infants is not associated with a higher incidence of major neurodevelopmental disability.
- These findings highlight significant advancements in neonatal care and improved long-term outcomes for EP infants.
Importance:
Survival of infants born extremely preterm (EP) (<28 weeks' gestation) has increased since the early 1990s. It is necessary to know whether increased survival is accompanied by increased neurodevelopmental disability.
Objective:
To examine changes in major (ie, moderate or severe) neurodevelopmental disability and survival free of major neurodevelopmental disability at 2 years in infants born EP.
Design, Setting, And Participants:
Four prospective longitudinal cohort studies comprising all EP live births at 22 to 27 weeks' gestation from April 1, 2016, to March 31, 2017, and earlier eras (1991-1992, 1997, and 2005), and contemporaneous term-born controls in the state of Victoria, Australia. Among 1208 live births during the periods studied, data were available for analysis of 2-year outcomes in 1152 children: 422 (1991-1992), 215 (1997), 263 (2005), and 252 (2016-2017). Data analysis was performed from September 17, 2020, to April 15, 2021.
Exposures:
Extreme preterm live birth.
Main Outcomes And Measures:
Survival, blindness, deafness, cerebral palsy, developmental delay, and neurodevelopmental disability at 2 years' corrected age. Developmental delay comprised a developmental quotient less than -1 SD relative to the control group means on the Bayley Scales for each era. Major neurodevelopmental disability comprised blindness, deafness, moderate to severe cerebral palsy, or a developmental quotient less than -2 SDs. Individual neurodevelopmental outcomes in each era were contrasted relative to the 2016-2017 cohort using logistic regression adjusted for gestational age, sex, birth weight z score, and sociodemographic variables. Changes in survival free of major neurodevelopmental disability over time were also assessed using logistic regression.
Results:
Survival to 2 years was highest in 2016-2017 (73% [215 of 293]) compared with earlier eras (1991-1992: 53% [225 of 428]; 1997: 70% [151 of 217]; 2005: 63% [170 of 270]). Blindness and deafness were uncommon (<3%). Cerebral palsy was less common in 2016-2017 (6%) than in earlier eras (1991-1992: 11%; 1997: 12%; 2005: 10%). There were no obvious changes in the rates of developmental quotient less than -2 SDs across eras (1991-1992: 18%; 1997: 22%; 2005: 7%; 2016-2017: 15%) or in rates of major neurodevelopmental disability (1991-1992: 20%; 1997: 26%; 2005: 15%; 2016-2017: 15%). Rates of survival free of major neurodevelopmental disability increased steadily over time: 42% (1991-1992), 51% (1997), 53% (2005), and 62% (2016-2017) (odds ratio, 1.30; 95% CI, 1.15-1.48 per decade; P < .001).
Conclusions And Relevance:
These findings suggest that survival free of major disability at age 2 years in children born EP has increased by an absolute 20% since the early 1990s. Increased survival has not been associated with increased neurodevelopmental disability.
