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APHA Scientific Session and Event Listing

Impact of multiple births and c-sections on the increasing low birthweight rate in the United States

Vani Bettegowda, MHS1, Rebecca Russell, MSPH1, Todd Dias, MS1, Michael Davidoff, MPH1, Karla Damus, PhD1, Howard Andrews, PhD2, and Joann Petrini, PhD1. (1) Perinatal Data Center, March of Dimes, 1275 Mamaroneck Avenue, White Plains, NY 10605, 914.997.4231, vbettegowda@marchofdimes.com, (2) Mailman School of Public Health, Columbia University, 722 West 168th Street, 6th Floor, New York, NY 10032

Over the past two decades, low birthweight (LBW, <2500 grams) in the U.S. has increased more than 16% (from 6.8% in 1981 to 7.9% in 2003). Rates of multiple births and c-sections, known contributors to the rise in LBW, have also increased in recent years, due in part to advances in infertility management and changes in obstetric practice. This study's purpose was to quantify the impact that these factors have had on the increase in LBW. Logistic regression was used to analyze 1996 and 2002 U.S. natality data from the National Center for Health Statistics. All analyses were stratified by race/ethnicity (non-Hispanic (NH) white, NH black) and maternal age (<20, 20-29, 30-39 and 40+). The unadjusted odds ratio (OR) for LBW in 2002 vs. 1996 was 1.06 (99% CI, 1.06-1.07). After adjusting for both multiple births and c-sections, the increase in LBW was smaller and not significant (OR=0.99; 99% CI, 0.98-1.00), indicating that the increase in multiple births and c-sections accounts for most of the rise in LBW. When analyzed by maternal race/ethnicity, the unadjusted OR for NH white infants indicated a 10% increase in LBW between 1996-2002 (OR=1.10, 99% CI 1.08-1.11), and a 3% increase among NH black infants (OR=1.03, 99% CI 1.01-1.04). Adjusting for multiple births and c-sections had the largest impact among NH white infants (OR=0.99, 99% CI 0.98-1.00). Additional analyses, including the effect of maternal age will be presented. Implications for programs, policies and clinical practice issues targeting the reduction of LBW will also be discussed.

Learning Objectives:

Presenting author's disclosure statement:

Not Answered

Maternal Health

The 134th Annual Meeting & Exposition (November 4-8, 2006) of APHA