How long is the latent phase of labour?

Objective: Modern delivery-room practices owe much to the studies of Doctor Friedman. However, the patients he considered had different features if compared to modern ones, as his studies were held in the last century. Doctor Friedman claimed that the latent phase of labour had to be considered prolonged if it was over 14 h for nulliparous women and over 20 h for multiparous women. In order to update these data, we have conducted a prospective cohort study to analyse the duration of latent phase of labour in our population. Methods: In our research we have taken into consideration women who were between the 37th and the 42nd week of gestation, with singleton physiological pregnancy and fetus in cephalic presentation, who presented to Niguarda Hospital in Milan between June 2009 and June 2010 for one of these conditions: contractile activity, premature rupture of membrane, blood loss. On the whole, we have collected 537 cases; among these, we have selected the ones whose first labour diagnosis proved to be right. The data have been accurately collected by two researchers. Overall, these patients have resulted being 308, of which 155 nulliparous and 153 multiparous. Results: Statistical analysis shows that in nulliparous women the average length of the latent phase is of 155 min (2.58 h) and the 95 centile takes 415 min (6.9 h), while for multiparous women the average length of the same phase is of 81 min (1.35 h) and the 95centile takes 315 min (5.25 ore). As a consequence, a nulliparous woman can be considered in a prolonged latent phase of labour if, after 7 h since contractions have begun, active labour has not started yet; a multiparous woman can be considered in a prolonged latent phase of labour if, after five and a half hours since contractions have begun, active labour has not started yet. Conclusion: Prolonged latent phase of labour is a condition that can lead to negative maternal-fetal outcomes. At present times, two types of intervention are proposed to solve the prolonged latent phase: it is possible to accelerate the labour, or, inversely, to sedate the patient, either pharmacologically or nonpharmacologically. Beyond personal beliefs, the most important thing is to ascertain whether the patient has entered the prolonged latent phase of labour, in order to intervene promptly and thus improve maternal.