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Am J Perinatol 2015; 32(10): 952-959
DOI: 10.1055/s-0035-1544191
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Hospital of Delivery and the Racial Differences in Late Preterm and Early-Term Labor Induction

Karna Murthy
1   Department of Pediatrics, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
2   Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
,
Michelle Macheras
3   Division of Neonatology, Department of Pediatrics, Children's Hospital of Philadelphia and the Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
,
William A. Grobman
4   Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
,
Scott A. Lorch
3   Division of Neonatology, Department of Pediatrics, Children's Hospital of Philadelphia and the Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
› Author Affiliations
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Publication History

10 July 2014

15 December 2014

Publication Date:
31 March 2015 (online)

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Abstract

Objectives To estimate the interhospital differences in induction of labor (IOL) from 340/7 to 386/7 weeks' gestation by race/ethnicity.

Methods Women between 34 and 42 weeks' gestation during 1995 and 2009 in three states were identified using linked maternal and infant records. Women with prior cesarean delivery, premature rupture of membranes, gestational hypertension, who delivered at hospitals with < 100 annual births, or who had missing data were excluded. The outcomes were inductions at early-term (ETI: between 370/7 and 386/7 weeks') and late preterm (LPI: from 340/7–366/7 weeks') gestations. Cox proportional hazard ratios (HR) were used to estimate the independent associations between race/ethnicity and hospital of delivery on ETI and LPI.

Results A total of 6.98 million eligible women delivered at 469 hospitals. ETI and LPI occurred in 3.20 and 0.40% of women, respectively. Non-Hispanic white women (3.99%) received ETI most commonly; conversely, LPI was highest among non-Hispanic black women (0.50%). In multivariable analyses, non-Hispanic black race was protective for ETI (HR = 0.89; p < 0.01) and was a risk factor for LPI (HR = 1.26; p < 0.01) after adjusting for patient factors and the delivery hospital.

Conclusion Racial differences in ETI and LPI appear to be pervasive. Much of the unaccounted racial/ethnic variation remains seems secondary to within-hospital differences in selecting women for IOL.

Keywords

epidemiology - induction of labor - late preterm - early-term - vital statistics
 

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