U.S. national trends in labor induction, 1989-1998.

Objective: To examine the epidemiology of labor induction in the United States.

Study Design: We used U.S. natality data from 1989 to 1998 and examined the rate of labor induction by year, geographic region, maternal characteristics and pregnancy complications.

Results: Between 1990 and 1998, the rate of labor induction increased from 9.5% to 19.4% of all births nationwide. However, the induction rate varied widely by state. White race, higher education and early initiation of prenatal care were associated with a higher rate of induction. For all gestational ages, a significantly increased induction rate occurred during the study period. The increase for clinically indicated induction was significantly slower than the overall increase, suggesting that elective induction has risen much more rapidly.

Conclusion: The rate of induction of labor more than doubled in the U.S. nationwide in the decade from 1989 to 1998. The increased use of labor induction may be attributable to both clinically indicated and elective induction.