The 130th Annual Meeting of APHA

Abstract #45596

Julia C. Rhodes, PhD¹, Kenneth C. Schoendorf, MD, MPH², and Jennifer D. Parker, PhD². (1) Epidemic Intelligence Service, Epidemiology Program Office, 1600 Clifton Road, Atlanta, GA 30333, 301-458-4664, jrhodes@cdc.gov, (2) Infant and Child Health Studies Branch, National Center for Health Statistics, 6525 Belcrest Road, Hyattsville, MD 20782

Background: After declining for a decade, cesarean section rates recently increased. To explore whether this is attributable to women gaining excessive weight during pregnancy resulting in macrosomic infants requiring delivery by c-section, we examined trends in excessive pregnancy weight gain, c-section, and macrosomia. Methods: Analysis of 1989-1999 birth certificate data was restricted to first birth, singleton infants >37 weeks gestation to avoid confounding by repeat c-section, complications of multi-gestational pregnancy, and prematurity. Excessive pregnancy weight gain was defined according to current guidelines (>40 lbs.) and macrosomia as birthweight >4000g. Results: From 1989-1997, the c-section rate decreased from 24.4% to 20.9%, then increased to 21.9% by 1999. Excessive weight gain rose from 18.6% to 24.2%. There was a 20.2% decline in macrosomic infants among excessive weight gain women compared to an 11.1% decline among other women, though the absolute risk remained greater among excessive weight gain women (e.g., 14.2% vs 8.9%, in 1999). C-sections declined by 17.8% among excessive weight gain women compared to 10.6% among other women; absolute risks in 1999 were 24.9% and 21.9%, respectively. Regardless of weight gain, macrosomic infants were consistently at higher risk of c-section compared with smaller infants. Overall, women gaining excessive weight accounted for 23.2% of c-sections in 1989 and 27.6% in 1999. Conclusions: Women gaining excessive weight during pregnancy account for a growing proportion of c-sections because their numbers are increasing and, despite their declining macrosomia and c-section rates, they remain at increased risk. Clinicians should encourage pregnancy weight gains within current guidelines.

Learning Objectives:

• Describe recent trends in cesarean section, excessive pregnancy weight gain, and macrosomia.
• Articulate the relationships between these factors.
• Recognize gaps in the literature on the impact of excessive pregnancy weight gain on cesarean section and construct future analyses to further our understanding of this issue.

Keywords: Pregnancy Outcomes, Weight Management

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.