The 131st Annual Meeting (November 15-19, 2003) of APHA

Abstract #69451

Rebecca Russell, MSPH¹, Joann Petrini, PhD, MPH¹, Michael Davidoff, MPH¹, Karalee Poschman², Karla Damus, RN, PhD¹, Howard Andrews, PhD³, and Nancy Green, MD⁴. (1) Perinatal Data Center, March of Dimes Birth Defects Foundation, 1275 Mamaroneck Ave, White Plains, NY 10605, 914-997.4683, rrussell@marchofdimes.com, (2) March of Dimes Birth Defects Foundation, Yale University, 1275 Mamaroneck Avenue, White Plains, NY 10605, (3) Center for Child Environmental Health, Columbia University, 1051 Riverside Drive, Box 47, New York, NY 10032, (4) March of Dimes, 1275 Mamaroneck Ave, White Plains, NY 10605

Preterm birth (PTB - less than 37 weeks gestation) rates have been shown to be higher among multiple births and c-section deliveries. The purpose of this study was to determine whether the increased rates of these factors account for the marked increased in U.S. PTB rates during the past five years. Logistic regression was used to analyze 1996 and 2000 U.S. natality data from the National Center for Health Statistics. The overall PTB rate increased from 11.0% in 1996 to 11.6% in 2000. The unadjusted odds ratio (OR) for PTB in 2000 vs. 1996 was 1.07 (95% CI, 1.06-1.07). After adjusting for multiple birth, the increase from 1996-2000 was smaller but still significant (OR=1.05; 95% CI, 1.05-1.06), indicating that the increase in multiples explains some but not all of the rise in PTB. Adjusting for c-sections had a similar effect (OR=1.05; 95% CI, 1.05-1.06). When analyzed by maternal race, the unadjusted OR for white infants indicated a 10% increase in PTB between 1996-2000 (OR=1.10, 95% CI 1.09-1.10) while PTB among black infants decreased slightly (OR=0.99, 95% CI 0.98-1.00). After adjustment, results indicated that the impact of multiples and c-sections on the overall trend in PTB was driven by white infants. There was no impact from these factors on the change among black infants. Additional analyses, including the effect of maternal age will be presented. Implications for programs targeting at reducing PTB will also be discussed.

Learning Objectives:

The participant will be able to:
• Discuss recent trends in preterm births in the United States.
• Describe the impact of multiple births and c-sections on the increase in the overall preterm birth rate in the United States.
• Recognize trends in preterm births by maternal race and the impact of multiple births and c-sections on these trends.

Keywords: MCH Epidemiology,

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.