Infants Born at 32-36 Weeks' Gestation and Subsequent School Performance
Infants Born at 32-36 Weeks' Gestation and Subsequent School Performance
Chyi LJ, Lee HC, Hintz SR, Gould JB, and Sutcliffe TL
J Pediatr. 2008;153:25-31. Epub 2008 Mar 19.
The study authors note that the percentage of births occurring in the 32- to 36-week gestation window is increasing, while the rate of children born before 32 weeks has remained essentially unchanged in recent decades. "Near-term" infants, born at 32-36 weeks' gestation, do not typically qualify for high-risk follow-up because the prevailing assumption is that they generally do as well as term newborns.
The authors tested that assumption in this study by analyzing a dataset of US public-school children which was developed by the US Department of Education and is available to the public. The sample is meant to be nationally representative. The dataset collected participants' pre-school medical history via parental report at school entry.
The authors divided the children in the dataset into 3 groups: "moderate preterm" (MP), born at 32-33 weeks' gestation; "late preterm" (LP), born at 34-36 weeks; and full-term (FT), born after 36 weeks.
The dataset allowed the authors to compare performance among these 3 groups when the groups were in kindergarten, 1st, 3rd, and 5th grades. The authors evaluated 3 outcomes of interest: results of direct assessment of the children using a battery of tests; teacher ratings of academic performance; and whether the child had either an individualized education plan (IEP) or was in special education classes.
The teacher ratings were on a 5-point scale ranging from "not yet" demonstrating proficiency to "proficient" for the skills evaluated in any particular question. The authors completed logistic regression for each of the 3 outcomes, with performance below the 50th percentile as the cutoff of interest. Regression included controls for sex, race, maternal education level, and poverty measures. Multiple-birth status correlated with outcome, but it also correlated with prematurity; because the prediction value would be the same, it was kept out of final regression models.
The dataset included 203 MP infants, 767 LP infants, and 13,671 FT infants. Attrition was always higher for subsequent follow-up with increasing prematurity, such that 5th-grade data were missing for 38.9% of MP infants, 34% of LP infants, and 32.4% of FT infants. However, the missing MP children had required greater services at early measures or performed worse than the missing FT children, suggesting that their higher rate of dropout also correlated with worse school performance.
Across all 3 outcome measures, infants who were MP or LP performed worse than FT infants. For example, in direct assessment, MP infants performed worse than FT infants in math in all 4 testing periods (kindergarten, 1st, 3rd, and 5th grades) and lower in reading in all grades except 3rd. In a similar pattern, the teacher academic rating was lower for MP infants in reading (all grades) and math (all grades after kindergarten). LP infants performed worse by direct observation or teacher evaluation in reading, but only in kindergarten or 1st grade. Overall, their performance in grades 3 and 5 was not different from that of FT children. In almost all grades, MP infants were more likely to require IEP or special education compared with FT infants, and LP children had greater rates of having an IEP or special education in kindergarten and 1st grades compared with FT children.
The authors concluded that infants born at 32-36 weeks' gestation are at higher risk for poor school performance than are infants born at full term.
These findings may come as a surprise to many readers. The authors excluded children who were preterm and had any notable perinatal complications, attempting to enroll only apparently healthy preterm infants. Unfortunately, because the data are presented as medians or means, it is difficult to assess what the difference in medians translates to for the children at the lower end of the spectrum. It could be that there is a substantial increase in the percentage of children below the 5th percentile of any measure. For example, moderate preterm infants required special education in 5th grade at a rate that was 76% higher than for full-term infants, resulting in a large increase in children performing below expectations.
Abstract
School Outcomes of Late Preterm Infants: Special Needs and Challenges for Infants Born at 32 to 36 Weeks Gestation
Chyi LJ, Lee HC, Hintz SR, Gould JB, and Sutcliffe TL
J Pediatr. 2008;153:25-31. Epub 2008 Mar 19.
Summary
The study authors note that the percentage of births occurring in the 32- to 36-week gestation window is increasing, while the rate of children born before 32 weeks has remained essentially unchanged in recent decades. "Near-term" infants, born at 32-36 weeks' gestation, do not typically qualify for high-risk follow-up because the prevailing assumption is that they generally do as well as term newborns.
The authors tested that assumption in this study by analyzing a dataset of US public-school children which was developed by the US Department of Education and is available to the public. The sample is meant to be nationally representative. The dataset collected participants' pre-school medical history via parental report at school entry.
The authors divided the children in the dataset into 3 groups: "moderate preterm" (MP), born at 32-33 weeks' gestation; "late preterm" (LP), born at 34-36 weeks; and full-term (FT), born after 36 weeks.
The dataset allowed the authors to compare performance among these 3 groups when the groups were in kindergarten, 1st, 3rd, and 5th grades. The authors evaluated 3 outcomes of interest: results of direct assessment of the children using a battery of tests; teacher ratings of academic performance; and whether the child had either an individualized education plan (IEP) or was in special education classes.
The teacher ratings were on a 5-point scale ranging from "not yet" demonstrating proficiency to "proficient" for the skills evaluated in any particular question. The authors completed logistic regression for each of the 3 outcomes, with performance below the 50th percentile as the cutoff of interest. Regression included controls for sex, race, maternal education level, and poverty measures. Multiple-birth status correlated with outcome, but it also correlated with prematurity; because the prediction value would be the same, it was kept out of final regression models.
The dataset included 203 MP infants, 767 LP infants, and 13,671 FT infants. Attrition was always higher for subsequent follow-up with increasing prematurity, such that 5th-grade data were missing for 38.9% of MP infants, 34% of LP infants, and 32.4% of FT infants. However, the missing MP children had required greater services at early measures or performed worse than the missing FT children, suggesting that their higher rate of dropout also correlated with worse school performance.
Across all 3 outcome measures, infants who were MP or LP performed worse than FT infants. For example, in direct assessment, MP infants performed worse than FT infants in math in all 4 testing periods (kindergarten, 1st, 3rd, and 5th grades) and lower in reading in all grades except 3rd. In a similar pattern, the teacher academic rating was lower for MP infants in reading (all grades) and math (all grades after kindergarten). LP infants performed worse by direct observation or teacher evaluation in reading, but only in kindergarten or 1st grade. Overall, their performance in grades 3 and 5 was not different from that of FT children. In almost all grades, MP infants were more likely to require IEP or special education compared with FT infants, and LP children had greater rates of having an IEP or special education in kindergarten and 1st grades compared with FT children.
The authors concluded that infants born at 32-36 weeks' gestation are at higher risk for poor school performance than are infants born at full term.
Viewpoint
These findings may come as a surprise to many readers. The authors excluded children who were preterm and had any notable perinatal complications, attempting to enroll only apparently healthy preterm infants. Unfortunately, because the data are presented as medians or means, it is difficult to assess what the difference in medians translates to for the children at the lower end of the spectrum. It could be that there is a substantial increase in the percentage of children below the 5th percentile of any measure. For example, moderate preterm infants required special education in 5th grade at a rate that was 76% higher than for full-term infants, resulting in a large increase in children performing below expectations.
Abstract
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