Misoprostol for induction of labour at term



We read with interest the recent randomised comparative trial by Danielian et al. and the systematic review by Hofmeyr et al. (Vol 106, August 1999)1,2 on the use of misoprostol as an agent for induction of labour. We believe that we are one of the few units in the UK to be using this preparation routinely for all women having induction of labour.

We compared the outcomes of 177 women between January and June 1997 whose labours were induced with dinoprostone with 243 women whose labours were induced between January and June 1998 with misoprostol. We demonstrated a significant difference in induction-to–delivery interval when misoprostol was compared with dinoprostone, a significant reduction in the use of oxytocin augmentation and a non-significant reduction in the instrumental delivery rate and caesarean section rate. We also compared umbilical venous pH, umbilical venous base excess, Apgar scores and admission to the special care baby unit between the two groups and could find no clinically important differences. There was a significantly increased rate of tachysystole in the misoprostol group but not of hyperstimulation. There were no untoward maternal or fetal events.

Both articles referred to above and the editorial comment in the same edition of the British Journal of Obstetrics and Gynaecology expressed caution with the use of misoprostol for routine induction of labour. One point made was that the increased pain in the group induced by misoprostol should limit its use but this has to be balanced against the much greater efficacy of the drug and all practising obstetricians will be familiar with the woman who remains undelivered after several days of dinoprostone. We have found that failed induction is very uncommon when misoprostol is used. Secondly, there are considerable cost savings involved in using this more effective induction agent. We have calculated that on the basis of reduced drug costs and a significantly shorter period of hospital stay our annual savings in a district general hospital with a delivery rate of 4200 was $69,000. Clearly safety concerns must be considered but Hofmeyr et al. and Danielian et al. could find no evidence of clinically adverse events and the latter also referred to two meta-analyses in his paper which came to similar conclusions.

We noticed that one of the authors of the systematic review by Hofmeyr et al. works with the WHO and yet the conclusion of their paper was that it should not be introduced into more widespread use without further controlled trials. We have this luxury in the West but we feel that the potential for the use of misoprostol could have been more positively commented on, particularly its use in the third world. One of the authors of this letter (R.H.) has had experience recently with obstetric units in the former Soviet Union and it is clear that misoprostol which is cheap, effective and does not require refrigeration has a powerful capacity to reduce maternal morbidity and mortality in countries where standard induction agents (i.e. dinoprostone) cannot be afforded or are in variable supply.