Trends in induction of labor at early-term gestation.

OBJECTIVE: To determine the trends and racial differences in early-term induction of labor in the United States. STUDY DESIGN: Data from the National Center for Health Statistics were used to identify women eligible for induction between 37-42 weeks' gestation in the United States from 1991-2006. Annual early-term induction rates were calculated, and maternal race/ethnicity was classified into 4 groups. The change in frequency and odds of early-term induction stratified by race/ethnicity over time was assessed. RESULTS: Among 39.2 million eligible women, early-term induction rates increased from 2.0% to 8.0% (P < .01) over 16 years. Cross-sectional and annual early-term induction rates were highest for non-Hispanic white women during the study period (P < .01). After adjusting for confounding factors, the odds of any early-term induction were highest (P < .01) and rose most rapidly (P < .01) among non-Hispanic white women compared with women from other racial/ethnic groups. CONCLUSION: In the United States, early-term induction rates rose significantly and were highest among non-Hispanic white women.