Objective. To determine the ability of the back-scratch test during early second trimester of pregnancy to predict the odd of caesarean section and the need of oxytocin administration to induce or stimulate labour. Design. Longitudinal study. Population or sample: Pregnant women from the GESTAFIT Project (n=157). Main Outcome Measures. Maternal upper-body flexibility was assessed at 16th gestational week through the back-scratch test. Type of birth and oxytocin administration was registered from the obstetric medical records. Results. The receiver operating characteristic curve analysis showed that the back-scratch test was able to discriminate between vaginal and caesarean section deliveries (area under the curve [AUC]=0.672 (95% confidence interval [CI]:0.60-0.77, p=0.002)). The AUC to establish the ability of the back-scratch test to detect the need of oxytocin administration was 0.682 (95% CI:0.59-0.78, p=0.001). In the adjusted model, a back-scratch test score <4.1 centimetres was associated to ~4 times greater increased odd ratio of having a caesarean section (95% CI:1.7-10.2, p=0.002). A back-scratch test score <3.6 centimetres was associated to ~5 times greater increased odd ratio of requiring exogenous oxytocin administration (95% CI:2.0-11.6, p=0.001). Conclusion. The back-scratch test discriminates pregnant women with greater risk of caesarean section from those with a vaginal delivery, and among those that will require oxytocin from those that will not. The early identification of pregnant women who fail to meet the suggested standards can help to easily, quickly and cheaply identify these relevant birth-related complications in order to initiate preventive strategies. Keywords. Pregnant woman, upper-body flexibility, labour, obstetric risk.