Prevalence of maternal obesity in an urban center.

OBJECTIVE

The purpose of this study was to evaluate the changing prevalence of maternal obesity in an urban center.

STUDY DESIGN

The prevalence of obesity in 31,542 pregnancies from January 1986 to December 1996 (group 1) was compared with the prevalence of obesity in 15,600 pregnancies between January 1997 and June 2001 (group 2). Maternal weight was divided into two groups according to measurements performed at delivery (<or=200 pounds and >200 pounds). Women who weighed >or=200 pounds were divided into subgroups for analysis (201-250 pounds, 251-300 pounds, and >300 pounds). The incidence of obesity by weight group was evaluated for a change over time; the impact of race and socioeconomic status was analyzed. A probability value of <.05 was considered significant.

RESULTS

Maternal obesity was significantly more common in group 2 (>200 pounds: 28% vs 21%; relative risk, 1.3; 95% CI, 1.3-1.4; 201-250 pounds: 20% vs 16%; relative risk, 1.3; 95% CI, 1.2-1.3; 251-300 pounds: 5.5% vs 3.7%; relative risk, 1.5; 95% CI, 1.3-1.6; >300 pounds: 1.6% vs 1.2%; relative risk, 1.4; 95% CI,1.2-1.7; P <.001 for each). Obesity was most common in African American women (>200 pounds, 28.1%; 201-250 pounds, 20.5%; 251-300 pounds, 5.5%; and >300 pounds, 2.1 %). The prevalence of obesity increased most among African American women (>200 pounds: 35 % vs 25%; relative risk, 1.4; 95% CI, 1.4-1.5; 201-250 pounds: 25 % vs 18%; relative risk, 1.4; 95% CI, 1.3-1.5; 251-300 pounds: 7.3 % vs 4.6%; relative risk, 1.6; 95% CI, 1.4-1.6; >300 pounds: 2.7% vs 1.8%; relative risk, 1.5; 95% CI, 1.3-1.9; P <.001 for each), and it decreased in Asian women (>200 pounds: 6.8% vs 11%; relative risk, 0.6; 95% CI, 0.4-0.9; P <.05; 201-250 pounds: 6.3% vs 9.7%; relative risk, 0.6; 95% CI, 0.4 -1.1; P >.05; 251-300 pounds: 0.6% vs 1%; relative risk, 0.6; 95% CI, 0.1- 2.9; P >.05; >300 pounds: 0.0% vs 0.3%). The increase in weight over time remained statistically significant after being controlled in multivariate analysis for socioeconomic status and race. Women with milder obesity (201-250 pounds prepregnancy weight) were at increased risk for preeclampsia, gestational and insulin-dependent diabetes mellitus, advanced gestational age (>or=42 weeks), fetal macrosomia, and cesarean delivery (P <.001 for each), with increasing weight being associated with higher risk.

CONCLUSION

Obesity that complicates pregnancy has increased significantly over the past 15 years. The risk of perinatal complications increases with increasing maternal pregravid weight; even those women with moderate obesity are at increased risk of adverse outcomes.