Maternal and Child Health Journal

, Volume 17, Issue 1, pp 33–41 | Cite as

Regional Variation in Late Preterm Births in North Carolina

  • Sofia R. Aliaga
  • P. Brian Smith
  • Wayne A. Price
  • Thomas S. Ivester
  • Kim Boggess
  • Sue Tolleson-Rinehart
  • Martin J. McCaffrey
  • Matthew M. Laughon


Late preterm (LPT) neonates (34 0/7th–36 6/7th weeks’ gestation) account for 70% of all premature births in the United States. LPT neonates have a higher morbidity and mortality risk than term neonates. LPT birth rates vary across geographic regions. Unwarranted variation is variation in medical care that cannot be explained by sociodemographic or medical risk factors; it represents differences in health system performance, including provider practice variation. The purpose of this study is to identify regional variation in LPT births in North Carolina that cannot be explained by sociodemographic or medical/obstetric risk factors. We searched the NC State Center for Health Statistics linked birth–death certificate database for all singleton term and LPT neonates born between 1999 and 2006. We used multivariable logistic regression analysis to control for socio-demographic and medical/obstetric risk factors. The main outcome was the percent of LPT birth in each of the six perinatal regions in North Carolina. We identified 884,304 neonates; 66,218 (7.5%) were LPT. After multivariable logistic regression, regions 2 (7.0%) and 6 (6.6%) had the highest adjusted percent of LPT birth. Analysis of a statewide birth cohort demonstrates regional variation in the incidence of LPT births among NC’s perinatal regions after adjustment for sociodemographic and medical risk factors. We speculate that provider practice variation might explain some of the remaining difference. This is an area where policy changes and quality improvement efforts can help reduce variation, and potentially decrease LPT births.


Late preterm Preterm birth Unwarranted variation Practice variation 



Dr. Smith received support from NICHD 1K23HD060040-01 and DHHS-1R18AE000028-01. Dr. Laughon receives support from the US government for his work in pediatric and neonatal clinical pharmacology (Government Contract HHSN267200700051C, PI: Benjamin) and from NICHD (1K23HL092225-01). We would like to thank the North Carolina State Center for Health Statistics and the Division of Medical Assistance at the North Carolina Department of Health and Human Services for providing access to the data used for this study.


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Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  • Sofia R. Aliaga
    • 4
  • P. Brian Smith
    • 2
  • Wayne A. Price
    • 1
  • Thomas S. Ivester
    • 3
  • Kim Boggess
    • 3
  • Sue Tolleson-Rinehart
    • 1
  • Martin J. McCaffrey
    • 1
  • Matthew M. Laughon
    • 1
  1. 1.Department of PediatricsUniversity of North CarolinaChapel HillUSA
  2. 2.Department of PediatricsDuke University Medical CenterDurhamUSA
  3. 3.Department of Obstetrics and GynecologyUniversity of North CarolinaChapel HillUSA
  4. 4.Department of PediatricsUniversity of North CarolinaChapel HillUSA

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