Temporal trends in the rates of trial of labor in low-risk pregnancies and their impact on the rates and success of vaginal birth after cesarean delivery.

OBJECTIVE

The national rate of vaginal birth after cesarean delivery decreased by 55% between 1996 and 2002. The objective of this investigation was to determine, in our population in upstate New York, whether this decline in the vaginal birth after cesarean delivery rate was due to temporal changes in the trial of labor rates or in the vaginal birth after cesarean delivery success rates.

STUDY DESIGN

Regional perinatal databases were used to obtain birth certificate data from a total of 135,833 live births in upstate New York from 1998 to 2002. Trial of labor, vaginal birth after cesarean delivery, and vaginal birth after cesarean delivery success rates were calculated for the 11,446 women who had had a previous cesarean delivery and a singleton, low-risk pregnancy at > or = 37 weeks of gestation. Additional factors that were analyzed included age, race, education, insurance, body mass index, parity, gestation, area of residence, prenatal care provider, size of hospital, and level of newborn nursery specialization. Tests for trends were conducted by year for each of the variables.

RESULTS

The trial of labor rate declined 39% from 58.7 in 1998 to 35.7 per 100 eligible women in 2002 (P < .01). The decline in trial of labor rates persisted after stratification within almost all groups (P < .01). The overall vaginal birth after cesarean delivery rate decreased 44%, from 42.7 in 1998 to 24.1 per 100 eligible women in 2002 (P < .01). The decline in vaginal birth after cesarean delivery rates persisted after stratification within almost all groups (P < .01). The rate of vaginal birth after cesarean delivery success was unchanged from 1998 to 2002 (P = not significant).

CONCLUSION

We found a major decline in trial of labor and vaginal birth after cesarean delivery rates in low-risk women from 1998 to 2002. There was no change in vaginal birth after cesarean delivery success in those patients who attempted trial of labor. This suggests that the decline in the vaginal birth after cesarean delivery rates that have been observed nationally may be due to a decline in trial of labor attempts and not to a change in vaginal birth after cesarean delivery success rates. The steep declines in trial of labor attempts and vaginal birth after cesarean deliveries suggest that there was a rapid change in the perception of optimal treatment practices for these patients by obstetricians.