Reliability of the Bishop score before labour induction at term.

OBJECTIVE

To evaluate the agreement within three pairs of observers regarding the Bishop score and an informal global evaluation of the cervix (favourable/unfavourable).

STUDY

DESIGN

We conducted a reliability study of the Bishop score. Three pairs of examiners (A-B, A-C and D-E) performed independently a cervical examination in 156 term pregnant women admitted for labour induction. We calculated the proportion of agreement and the Kappa coefficient.

RESULTS

Perfect agreement between two observers for the Bishop score was found in 44 women (28%). Accepting a difference of one point between the observers, agreement increased to 66%. Weighted Kappa coefficients for the Bishop score were 69, 54 and 35% for each pair of observers. Kappa coefficients for the informal evaluation of the cervix were 64, 45 and 46, respectively.

CONCLUSION

Agreement between two observers evaluating the cervix is fair to substantial. An informal evaluation of the cervix is as reliable as the Bishop score.