A key sign of an obstructed labour is if the widest diameter of the fetal skull remains stationary above the pelvic brim because it is unable to descend. You should be able to detect this by careful palpation of the mother's abdomen as the uterus relaxes and softens between contractions. However, if the uterus has gone into tonic contraction (it is continuously hard) and sits tightly moulded around the fetus, it will be very difficult to feel whether the fetus is making any progress in the birth canal. Palpation will also be very painful for the woman. In this case you will have to rely more on other signs for your diagnosis, listed below.