Introduction: The partograph is used for identifying anomalies in the progression of the delivery labor and indicating the moment for accelerating it before the delivery labor is affected. The maternal and fetal prognosis remains reserved in our hospitals despite the correct use of the partograph. Aim: To establish a tool that can predict the outcome of the delivery labor at the end of the cervical latency phase. Method: we carried out a case-control study for diagnosis at the General Referral Hospital of Oïcha. Inclusion criteria: primiparous parturient at the beginning of delivery labor, with mono fetal pregnancy at term, live fetus, cephalic top presentation. At the end of the latent phase of the cervix: calculation, using the protractor, of the adjacent angle to the hypotenuse formed by the time vector and the equipollent of the dilation vector. Distribution of subjects in 2 groups: those with angle <45° (n = 314) compared to those with angle ≥45° (n = 314). The association between the different variables tested in bi-varied analysis by the Pearson chi- square; the association strength by multivariate analysis of significant independent variables (p <0.05) with conditional logistic regression. Results: The angle <45° was associated with: velocity of dilation <1cm / hour in the active dilation phase, delivery labor dragging, Caesarean section, low Apgar score in the 5th minute. Conclusion: The latency phase has an impact on maternal and fetal prognosis. The calculation of the angle adjacent to the hypotenuse at the end of this phase is useful for early adjustment of work management.
