3.4 Monitoring the Progress of Labour

The assessment of the progress of labour is made by observation of the woman; her appearance, behaviour, contractions, and the descent of the presenting part. The most accurate measure is dilatation of the cervix. Deviation from an arbitrarily defined normal rate of dilatation should be an indication for review of the labour management plans. In the partograph method of WHO (WHO 1993) the alert line is passed if the dilatation is slower than 1 cm per hour; if the woman is in a health centre this is reason to refer her to a hospital. The action line is passed if delay in progress continues for four more hours. Then a critical assessment of the cause of delay should be made, and a decision taken about the appropriate management. Although these strict rules are not followed in all countries, they form valuable guidelines, especially in those situations where distances to a referral centre are great, and birth attendants are isolated. Research about the effect of the use of the partograph showed that over a fifth of the graphs of primigravidae crossed the alert line, and 10-11% crossed the action line (Philpott and Castle 1972, WHO 1994b). In Latin America a different partograph is in use, differentiating between nulliparous and multiparous women, intact and ruptured membranes, and upright or lying position (Schwarcz et al 1987-1995).

The relationship between prolonged labour and adverse maternal and fetal outcome is the reason why it is so important to monitor the progress of labour accurately. The extent to which that relationship is causal is by no means certain. Slow progress should be a reason for evaluation rather than for intervention. Cephalopelvic disproportion must be considered when progress is slow. Intrapartum X-ray pelvimetry has not proven to be useful. The available trials of X-ray pelvimetry show an increase of interventions like caesarean section, but no benefits in terms of reduced neonatal morbidity (Parsons and Spellacy 1985). X-ray pelvimetry during pregnancy and labour increases the incidence of leukaemia in infancy, and should be abolished (Stewart et al 1956, MacMahon 1962). In experienced hands manual pelvimetry may be useful. If the membranes are still intact during labour slow progress is usually not caused by disproportion. Expectant management would then be an option (Albers et al 1996). As no solid research evidence is available about expectant management versus active management in case of slow progress without signs of disproportion, no definite conclusions can be drawn. When the membranes are ruptured slow progress is more likely to be the consequence of mechanical problems. The management in cases of abnormal labour is beyond the scope of this report.