Racial differences in the patterns of preterm delivery in central North Carolina, USA

Authors

  • Cheryl A. Blackmore,

    Corresponding author
    1. *Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia
    2. †Departments of Epidemiology University of North Carolina School of Public Health
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  • David A. Savitz,

    1. †Departments of Epidemiology University of North Carolina School of Public Health
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  • Lloyd J. Edwards,

    1. ‡Departments of Biostatistics, University of North Carolina School of Public Health
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  • Sioban D. Harlow,

    1. §Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
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  • Watson A. Bowes Jr.

    1. ¶Department of Obstetrics and Gynecology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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Division of Reproductive Health, Centers for Disease Control and Prevention, 4770 Buford Highway, NE, Mail Stop K23, Atlanta, GA 30341-3724, USA.

Abstract

Summary. In order to assess racial differences in rates of idiopathic preterm labour, preterm premature rupture of membranes, and medically indicated preterm delivery, the authors analysed data on 388 preterm (< 37 completed weeks of gestation) births (7.9% of all births) occurring between 1 September 1988 and 31 August 1989, in three central North Carolina counties. The crude relative risk (RR) of preterm birth among black women compared with white women was 2.6 [95% confidence interval (CI) 2.1, 3.1]. With adjustment for age, gravidity, marital status, education, and county of residence, the estimated relative risk for black women compared with white women was 2.1 (95% CI 1.1,4.1) for medically indicated preterm delivery, 1.6 (95% CI 1.1,2.3) for preterm birth as a result of preterm labour, and 1.9 (95% CI 1.2,3.1) for preterm premature rupture of membranes. Compared with white women, black women were at the highest risk of a preterm birth before 34 weeks of gestation (RR = 2.9; 95% CI 1.8, 4.7). The risk of medically indicated preterm delivery at 36 weeks was considerably higher for black women than for white women (RR = 3.4; 95% CI 1.1,10.2). For a better understanding and ultimately a reduction of the risk for preterm delivery among black women, investigation of specific aetiological pathways and gestational age groups may be required.

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