Abstract
The influence of prostaglandin E1 (PGE1), oxytocin and methyl ergometrin maleate (Mether-gin®) on the contractility of the pregnant human uterus was compared in in vivo experiments on 8 early pregnant and 14 midpregnant women. The substances were administered intravenously in separate injections. With the doses used PGE1 and oxytocin caused a marked elevation of tone whereas Methergin® had a less significant effect. The duration of the elevation of tone after PGE1 was approximately three times longer than that after oxytocin but considerably shorter than after Methergin®. The motility pattern following Methergin® was characterized by small irregular contractions which differed completely from that after PGE1 and oxytocin. The pharmacological effect of PGE1 on the midpregnant uterus suggests that this substance might reduce blood loss and shorten the period of time for placental separation during the third stage of labour. However, this assumption could not be confirmed as judged from a small clinical pilot study carried out on 188 women.