Elsevier

The Journal of Pediatrics

Volume 154, Issue 2, February 2009, Pages 169-176.e3
The Journal of Pediatrics

Original article
Increased Risk of Adverse Neurological Development for Late Preterm Infants

https://doi.org/10.1016/j.jpeds.2008.08.020Get rights and content

Objective

To assess the risks of moderate prematurity for cerebral palsy (CP), developmental delay/mental retardation (DD/MR), and seizure disorders in early childhood.

Study design

Retrospective cohort study using hospitalization and outpatient databases from the Northern California Kaiser Permanente Medical Care Program. Data covered 141 321 children ≥30 weeks born between Jan 1, 2000, and June 30, 2004, with follow-up through Jun 30, 2005. Presence of CP, DD/MR, and seizures was based on International Classification of Diseases, Ninth Revision codes identified in the encounter data. Separate Cox proportional hazard models were used for each of the outcomes, with crude and adjusted hazard ratios calculated for each gestational age group.

Results

Decreasing gestational age was associated with increased incidence of CP and DD/MR, even for those born at 34 to 36 weeks gestation. Children born late preterm were >3 times as likely (hazard ratio, 3.39; 95% CI, 2.54-4.52) as children born at term to be diagnosed with CP. A modest association with DD/MR was found for children born at 34 to 36 weeks (hazard ratio, 1.25; 95% CI, 1.01-1.54), but not for children in whom seizures were diagnosed.

Conclusions

Prematurity is associated with long-term neurodevelopmental consequences, with risks increasing as gestation decreases, even in infants born at 34 to 36 weeks.

Section snippets

Study Population

The sample for this study was drawn from the Northern California KPMCP, the characteristics and information systems of which were described in detail in earlier reports.17, 20, 21, 22, 23, 27, 28, 29 To be eligible for the study, children had to: 1) born alive at 1 of the 12 KPMCP birth facilities (the KPMCP medical centers at Fresno, Hayward, Oakland, Redwood City, Sacramento, San Francisco, Santa Clara, Santa Rosa, Santa Teresa, South Sacramento, Vallejo, and Walnut Creek) between Jan 1,

Analysis Dataset

A total of 142 735 children born at ≥30 weeks gestation were included in the initial dataset. Of these, 144 records were excluded because the infant died during the birth hospitalization, 12 records were excluded because of missing sex, 1 record with a clearly erroneous birth weight was excluded, and 1257 records were excluded because the infant did not have at least 1 day of follow-up time. Follow-up time was defined as the date of the last visit identified in the medical record minus the

Discussion

On the basis of a contemporary dataset from which children born extremely premature (<30 weeks) were excluded, this study demonstrates that moderate prematurity confers an increased risk for CP and DD/MR beyond infancy. Most important, we demonstrate a 3-fold increased risk of CP and significantly higher rates of DD/MR for late preterm infants compared with term infants. A total of 2.1% of the late preterm infants in our study population were identified as having CP, DD/MR, or seizures compared

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  • Cited by (0)

    This research was supported by the March of Dimes, The Permanente Medical Group, Inc. and Kaiser Foundation Hospitals, Inc. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the affiliated agencies. The authors declare no conflicts of interest.

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