|Care in Normal Birth (WHO, 1996, 60 p.)|
|3. CARE DURING THE FIRST STAGE OF LABOUR|
|3.5 Prevention of Prolonged Labour|
Several measures have been proposed to prevent delay in the progress of labour; sometimes these actions are taken long before the action line or even the alert line of the partograph are reached. The most active interventions are early amniotomy and early oxytocin infusion, or a combination of the two. Early amniotomy interferes with the physiological timing of fetal membranes rupture. Under normal conditions, the membranes remain intact until full dilatation in 75% of the cases (Schwarcz et al 1995). Amniotomy before full dilatation is frequently practised as a method to expedite labour.
This intervention has been recommended as a routine procedure 1 hour after admission in labour (ODriscoll et al 1973). In a controlled study a considerable increase of type I decelerations of the fetal heart rate was found after early amniotomy (Schwarcz et al 1973). Several randomized trials suggest that amniotomy early in labour leads to a reduction, on average, of between 60 and 120 minutes in the duration of labour, without effects on the use of analgesia and rates of operative delivery. The trials provide no evidence that early amniotomy has a favourable or unfavourable effect on the condition of the neonate (Fraser et al 1991, 1993, Barrett et al 1992). It is not possible to conclude that early amniotomy has a clear advantage over expectant management, or the reverse. Therefore, in normal labour there should be a valid reason to interfere with the spontaneous timing of the rupture of the membranes.
This is frequently used to expedite labour after either spontaneous or artificial rupture of the membranes. The combination with early amniotomy is often called active management of labour, and as such it was first advocated in Ireland (ODriscoll et al 1973, ODriscoll and Meagher 1986). In more or less modified form the technique has been widely adopted across the world. According to the original protocols for the active management of labour, after early amniotomy hourly vaginal examinations are performed, and oxytocin is administered if the rate of cervical dilatation is less than 1 cm per hour. The practice has been investigated in a number of randomized trials (Read et al 1981, Hemminki et al 1985, Bidgood and Steer 1987, Cohen et al 1987, Lopez-Zeno et al 1992). Of the three trials providing data on the length of labour after oxytocin augmentation compared to control groups, only one showed a shorter mean duration with oxytocin. In one trial the women in the control group were encouraged to get out of bed and walk around, stand or sit as they wished. In this control group the mean duration of labour was slightly shorter than in the augmented group. Neither Apgar scores nor the incidence of admission to a special care nursery were different between oxytocin augmentation and control groups (Hemminki et al 1985). This study reported on the womens views on the procedure. The majority said the augmentation procedure was unpleasant. More than 80% felt that augmentation had increased their pain. Half of the women in the control group who were ambulant said that this mobility had decreased their pain while 24% felt no difference.
In conclusion, it is not clear from the available data that liberal use of oxytocin augmentation (active management of labour) is of benefit to women and babies. Of course this does not mean that oxytocin is useless in the therapy of prolonged labour. However, there is no evidence that the prevention of prolonged labour by the liberal use of oxytocin in normal labour is beneficial. It is fair to ask whether labour augmented by oxytocin infusion can still be considered normal. In many places oxytocin infusions are only administered in hospital under the responsibility of the obstetrician. This is a reasonable precaution, given the unpredictable nature of artificially managed labour. As a general rule oxytocin should only ever be used to augment labour in facilities where there is immediate access to caesarean section should the need arise. The need for augmentation is considered an indication for referral to obstetric services with surgical facilities. Where available, subsequent fetal surveillance is not by intermittent auscultation but by electronic monitoring. The experience in Dublin during the randomized trial of intrapartum fetal heart rate monitoring also points in this direction: in the group monitored with auscultation the number of neonatal seizures was increased, but the majority of these infants were born from mothers who had augmentation with oxytocin during labour (MacDonald et al 1985). See also 2.7 Oxytocin augmentation is a major intervention and should only be implemented on a valid indication. The same holds true for the more modern variation of augmentation with prostaglandins, and for the induction of labour with these substances.
Use of any intramuscular oxytocic before the birth of the infant is generally regarded as dangerous, because the dosage cannot be adapted to the level of uterine activity. Hyperstimulation may result and is harmful to the fetus. An increase in the incidence of ruptured uterus, with corresponding grave sequelae, has also been linked to this practice (Kone 1993, Zheng 1994). Nevertheless intramuscular oxytocin administration is still practised, sometimes at the request of pregnant women or her family expecting a more rapid delivery. In some developing countries the drug can be bought on the market. This harmful practice should be abandoned. The same holds true for the administration of other oxytocics, like prostaglandins, at any time before delivery in such a way that their effect cannot be controlled.