Intermittent low-dose administration of prostaglandins intraamniotically in pathological pregnancies. A comparison with oxytocin and ergometrine.

The effects of prostaglandin F2 alpha on uterine contractility were compared with the effects of oxytocin and ergometrine. All patients had an intrauterine death. 5 patients were induced with prostaglandin F2 alpha, given intraamniotically in low doses, starting with 125 micrograms. Doses were increased in relation to uterine activity. 5 other patients were induced by intravenous administration of oxytocin and ergometrine. Uterine pressure was monitored by a transabdominal open-tip catheter system. Results were quantitated in tonus (mm Hg), amplitude (mm Hg), frequency (number of contractions per 10 min), Montevideo units, active and total pressure areas per 20 min. Possible biochemical and coagulation changes were controlled before, during and after induction. Changes did not occur. Intermittent increasing small doses of PGF2 alpha increased uterine activity exponentially. Hypertonia persisting longer than 5 min was seldom seen with oxytocin or with PGF2 alpha. Ergometrine increased frequency of uterine contractions, without influencing tonus, probably due to a specific effect on the 'archemyometrium'. The induction-delivery interval was shorter in the PGF2 alpha group (range: 6-15 h) than in the oxytocin group (range: 7-24 h). In the latter group more inductions were necessary to complete delivery. Using PGF2 alpha in these small doses did not cause any side effects. With the intraamniotic injections, starting with 125 micrograms PGF2 alpha, clinical results are the same as those reported in the literature for high doses.