Lack of utility of standard labor curves in the prediction of progression during labor induction.

OBJECTIVE: This study was undertaken to determine whether patients undergoing labor induction can be reliably evaluated by means of standard labor assessment curves.

STUDY DESIGN: In this retrospective chart review of 123 patients who underwent cervical ripening and induction of labor, Friedman's standard labor curves were used for comparison. Statistical analysis was performed with the Student t test.

RESULTS: Nulliparous and parous patients undergoing cervical ripening spent more time in active-phase labor than standard expectations of labor progression would indicate (12.7 +/- 7.8 vs 5. 9 +/- 3.4 hours for nulliparous women, P <.001; 7.9 +/- 6.4 vs 2.5 +/- 1.5 hours for parous women, P <.001). Nulliparous and parous patients who were delivered vaginally spent more time in active labor than did their respective standard historical control populations (10.3 +/- 8.0 vs 5.9 +/- 3.4 hours for nulliparous women, P <.001; 7.0 +/- 6.0 vs 2.5 +/- 1.5 hours for parous women, P <. 001).

CONCLUSION: Standard methods for the evaluation of labor adequacy and prediction of the likelihood of vaginal delivery may not apply to patients undergoing cervical ripening.