Comparison of induction of labour regimes for termination of pregnancy, with and without mifepristone, from 20 to 41 weeks gestation

Aim: To investigate the efficacy of mifepristone for induction of labour in pregnancies at 20-41 weeks' gestation, by comparing the outcomes of length of labour and duration of admission in women with and without mifepristone pretreatment.

Method: In this retrospective cohort study, all women who underwent a medical termination of a singleton pregnancy between 20 and 41 weeks gestation for either a fetal abnormality or fetal death in utero between 1 January, 2009 and 1 January, 2014 were identified. Women who went into spontaneous labour, required a primary surgical delivery or had a multiple pregnancy were not included.

Results: The total number of women included in the study was 147: 63 in the mifepristone treatment and 84 in the no mifepristone treatment. In the group of women induced after mifepristone pre-treatment there was a 38% reduction in the median duration of labour, with 2.5 h in the group treated with mifepristone versus 4.0 h in women induced without (P = 0.001). We also found a 50% reduction in the number of days admitted to hospital with the length of admission being 1 day versus 2 days (P = 0.005).

Conclusion: This study supports the hypothesis that in pregnancies greater than 20 weeks, the duration of labour and length of admission are reduced when induction of labour for termination of pregnancy is preceded by treatment with mifepristone.