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Peripheral plasma concentrations of 13,14-dihydro-15-keto prostaglandin F (PGFM) were measured in three groups of women after the 37th week of pregnancy. Samples were taken before and five minutes after (a) amniotomy, (b) vaginal examination with sweeping of the fetal membranes, or (c) vaginal examination without sweeping of the membranes. Each procedure significantly raised the circulating PGFM levels, although amniotomy and vaginal examination with membrane sweep were more potent stimuli than vaginal examination alone. These findings suggest that there is a considerable potential for rapid increases in prostaglandin production during late pregnancy and provide a possible explanation for the fact that amniotomy and vaginal examination with membrane sweep often initiate labour.

A retrospective survey of 658 consecutive deliveries in Aberdeen Maternity Hospital in 1970 showed that fetal distress, low Apgar score at five minutes, and special nursery admission were all common in patients receiving oxytocin infusion. Many patients receiving such infusions also had very frequent contractions when compared with others. Though the populations in each group were not standard, the clinical criteria were crude, and the survey was retrospective there are resonable grounds to believe that the present enthusiasm for oxytocin has perhaps led us in clinical practice to underestimate and forget the dangers of oxytocin to the fetus. Careful monitoring of the fetus of the mother receiving oxytocin is essential.

A prospective study of 1,000 consecutive primigravid deliveries has shown that active management in labour can ensure that every woman is delivered within 24 hours. Emphasis is laid on the importance of a correct initial diagnosis of labour based on objective criteria. Amniotomy followed by oxytocin infusion is advocated to simulate the progress of normal labour unless this is evident from an early stage.Oxytocin, the dose of which is limited only by foetal distress, cannot be used effectively unless three popular fallacies are rejected. Firstly, that prolonged labour is often an expression of cephalo-pelvic disproportion; secondly, that oxytocin may rupture the primigravid uterus; and, thirdly, that there is a valid therapeutic distinction between hypotonic and hypertonic uterine action.Stimulation, properly supervised, is safe to mother and child, it eliminates the problem of occipitoposterior position, results in a sharp decline in forceps delivery, and obviates the need for massive analgesia.

Of 2,272 deliveries between 1 October, 1967 and 31 December, 1968 290 were induced by simultaneous intravenous Syntocinon (synthetic oxytocin) at amniotomy. The hazards of induction of labour are greatly reduced when this method is used routinely. Only 4 of the 13 caesarean sections were thought to be due to failure of method. Within 12 hours 221 patients were delivered, and this short induction-delivery interval resulted in an extremely low maternal and fetal morbidity. It is believed that with proper safeguards and in the light of present knowledge this is the method of choice.

In a group of 20 matched primigravid patients labour was induced by forewater amniotomy followed by intravenous oxytocin (Syntocinon) administered in escalating doses. Ten of these patients, in a double-blind trial, also received prostaglandin E(2) infused simultaneously with the oxytocin. In the combined prostaglandin-oxytocin group there was a noticeable reduction in the dosage of oxytocin required to produce effective uterine action, and the duration of labour was also reduced. No side effects were observed.