The effects of mifepristone on uterine sensitivity to oxytocin and on fetal heart rate patterns.

OBJECTIVE

To compare the incidences of tachysystole, hypertonia and fetal heart rate (FHR) abnormalities in women treated by mifepristone plus prostaglandins (PGs), mifepristone alone or PGs alone for an unfavourable cervix.

STUDY

DESIGN

In this retrospective study, all women between 37 and 42 weeks were eligible for the study if they had undergone cervical ripening prior to labour induction. In group 1, the women were treated with mifepristone plus PGs (n=103). Group 2 women were treated with mifepristone alone (n=96) and group 3 women with PGs alone (n=100). Incidences of tachysystole, hypertonia and FHR abnormalities were compared.

RESULTS

During induction of labour, tachysystole and hypertonia occurred more frequently in women treated with mifepristone. Severe bradycardia and recurrent late decelerations were more frequent after the initiation of oxytocin in groups 1 and 2 than in group 3.

CONCLUSIONS

In this study, mifepristone increased the incidences of tachysystole, hypertonia and FHR abnormality.