Induction of Labor by Intra-Cervical Pge₂ in Viscous Gel: Mechanism of Action and Clinical Treatment Routines

Abstract

Induction of labor in women with immature cervix was accomplished by four different treatment schedules. the case material included a total of 100 subjects, each treatment group having 25 cases:

Group A: Intravenous oxytocin;

Group B: Intracervical PGE₂-gel followed by intravenous oxytocin;

Group C: Intracervical PGE₂-gel twice with a 12-hour interval;

Group D: Intracervical placebo gel twice with 12-hour interval.

Oxytocin did not influence the Bishop score (B.S.) unless in the presence of active labor contractions. in contrast, there was an increment in B.S. by 3.6 points on average within 12 hours following PGE₂-gel as calculated from data of subjects without signs of contractions. These results support the concept of a local action of PGE₂-gel. the increment in B.S. was larger in subjects with very immature cervices (B.S. ⩽2) than in those with moderately immature scores (B.S. 4). a second PGE₂-gel instillation did not increase the B.S. above the level achieved by the first application, indicating that pharmacological ripening of the cervix by a single dose of PGE₂ results in an effect approaching maximum.

The success rate was the same for oxytocin and PGE₂-gel treated women during the first 24 hours, when approximately 40% of the women had given birth. the oxytocin group remained at that level of success rate, whereas the PGE₂-gel-oxytocin and PGE₂-gel × 2 series continued to improve their success rate up to 75%. An interesting finding in the study was that women given PGE₂-gel twice did not need intravenous oxytocin stimulation except in a few cases.

Key Words:

• Induction of labor
• prostaglandins