Evaluation of a controlled release vaginal prostaglandin E2 pessary with a retrieval system for the induction of labour

Summary Summary A slow release hydrogel polymer prostaglandin E2 pessary with a retrieval system for the induction of labour was studied in III women with a cervical score ≤6. The pessary was removed with little difficulty and caused no discomfort while in situ in 97 per cent of cases. The mean prostaglandin E2 release rate, assessed by high performance liquid chromatography, was 0·33±0·15 mg/hour (s.d.; 95 per cent confidence interval 0·30-0·36 mg/hour) and was not related to parity, treatment success or failure. There was no dose dumping. Four cases (4 per cent) had fetal heart rate abnormalities during induction, none were hyperstimulated. Two cases (2 per cent) of hyperstimulation resolved with removal of the pessary and in neither case was more than 1 mg of prostaglandin E2 released from the pessary. This preparation safely allows the obstetrician to control the dose of prostaglandin E2 administered during induction of labour.