Features of Cervical Ripeness

The success in attaining labor through induction depends upon certain features of the cervix, referred to as the ripeness of the cervix, the most important of which include:

  • Dilation of the cervix;
  • Effacement (thinning) of the cervix;
  • Station of the presenting part of the fetus (usually the head) in the birth canal;
  • Consistency of the cervix; and
  • Position of the cervix.

These features are related to biochemical and physical changes naturally occurring in the cervix as the onset of labor approaches and are fairly easy to assess by an experienced obstetrician feeling the cervix and the presenting part of the baby.

Bishop Scoring System

The Bishop scoring system uses these features, especially the dilation and effacement of the cervix, to determine whether the cervix is favorable for the induction of labor.

Table 1. The Bishop scoring system to determine cervical status
11-2 cm40-50%-2MediumMidposition
23-4 cm60-70%-1 or 0SoftAnterior
35 cm80%+1 or +2
  • In women who have previously given birth, Bishop scores of nine or more are associated with a high rate of successful labor induction.
  • Only about half of women with a score of four or less achieve successful labor.

In common medical terminology, the status of the cervix is considered favorable if it suggests a successful induction of labor and a high likelihood of vaginal birth. The status is considered unfavorable if it suggests a low likelihood of achieving successful induction of labor.