OBSTETRICS Association between prepregnancy body mass index and congenital heart defects Suzanne M. Gilboa, PhD; Adolfo Correa, MD, PhD; Lorenzo D. Botto, MD; Sonja A. Rasmussen, MD, MS; D. Kim Waller, PhD; Charlotte A. Hobbs, MD, PhD; Mario A. Cleves, PhD; Tiffany J. Riehle-Colarusso, MD, MSE; and the National Birth Defects Prevention Study OBJECTIVE: The purpose of this study was to examine associations be- tween prepregnancy body mass index (BMI) and congenital heart de- fects (CHDs). STUDY DESIGN: These analyses included case infants with CHDs (n = 6440) and liveborn control infants without birth defects (n = 5673) en- rolled in the National Birth Defects Prevention Study (1997-2004). RESULTS: Adjusted odds ratios for all CHDs combined were 1.16 (95% confidence interval [CI], 1.05–1.29), 1.15 (95% CI, 1.00 –1.32), and 1.31 (95% CI, 1.11–1.56) for overweight status, moderate obesity, and severe obesity, respectively. Phenotypes as- sociated with elevated BMI (25.0 kg/m 2 ) were conotruncal de- fects (tetralogy of Fallot), total anomalous pulmonary venous return, hypoplastic left heart syndrome, right ventricular outflow tract (RVOT) defects (pulmonary valve stenosis), and septal defects (se- cundum atrial septal defect). CONCLUSION: These results corroborated those of previous studies and suggested new associations between obesity and conotruncal de- fects and RVOT defects. Key words: body mass index, congenital heart defects, gestational diabetes, obesity Cite this article as: Gilboa SM, Correa A, Botto LD, et al. Association between prepregnancy body mass index and congenital heart defects. Am J Obstet Gynecol 2010;202:51.e1-10. C ongenital heart defects (CHDs) are among the most common types of birth defects 1 and are a leading cause of birth defects-associated morbidity, mor- tality, and medical expenditures. 2-4 Pre- gestational diabetes mellitus (PGDM) is a recognized risk factor for CHDs. 5,6 Given this relationship, other conditions that are associated with alterations in glycemic control, such as prepregnancy overweight status and obesity, have been considered potential risk factors for CHDs. 7-14 The prevalence of prepregnancy obe- sity has risen substantially in the last 15 years: 1 recent study that included data from 9 states suggested the prevalence of prepregnancy obesity increased from 13% to 22% (nearly a 70% increase) from 1993 to 2003. 15 Women who are obese are at increased risk for gestational diabetes mellitus (GDM) and hyperten- sion, and pregnancies among women who are obese are at increased risk for several adverse outcomes, including fetal death, macrosomia, and large for gesta- tional age. 16-21 Several studies also have suggested that increased body mass index (BMI) is associated with delivering an infant with a birth defect. 7-14,22-25 A metaanalysis fo- cusing on neural tube defects (NTDs) es- timated overall odds ratios (ORs) for an NTD-affected pregnancy of 1.22 (95% confidence interval [CI], 0.99 –1.49) for mothers who are overweight, 1.70 (95% CI, 1.34 –2.15), for mothers who are moderately obese, and 3.11 (95% CI, 1.75–5.46) for mothers who are severely obese, compared with mothers of nor- mal weight. 26 With respect to CHDs, the literature has been less consistent. 7-14 Most studies have shown weak associations between overweight status, obesity, or both and all CHDs combined, 7,8,11-13 with a few studies suggesting associations with spe- cific phenotypes, such as ventricular sep- tal defects, 7,12 atrial septal defects, 7,12 and left ventricular outflow tract (LVOT) defects. 12 Two California anal- yses found no association with the From the National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA (Drs Gilboa, Correa, Rasmussen, and Riehle- Colarusso); the Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT (Dr Botto); the School of Public Health, University of Texas Health Sciences Center at Houston, Houston, TX (Dr Waller); and the Department of Pediatrics, Birth Defects Research Section, University of Arkansas for Medical Sciences and Arkansas Children’s Hospital Research Institute, Little Rock, AR (Drs Hobbs and Cleves). Presented at the 13th Annual Maternal and Child Health Epidemiology Conference, Atlanta, GA, Dec. 10-12, 2007. Received Jan. 21, 2009; revised July 9, 2009; accepted Aug. 6, 2009. Reprints not available from the authors. This work was supported in part through cooperative agreements under Program Announcement #02081 from the Centers for Disease Control and Prevention to the centers participating in the National Birth Defects Prevention Study. The views expressed herein are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. 0002-9378/$36.00 • Published by Mosby, Inc. • doi: 10.1016/j.ajog.2009.08.005 Research www. AJOG.org JANUARY 2010 American Journal of Obstetrics & Gynecology 51.e1