Obstructed labour occurs when the vaginal delivery of the fetus is arrested due to a mechanical obstruction. It can be caused by maternal factors like a contracted pelvis or fetal macrosomia. Diagnosis involves a clinical examination showing signs of maternal distress, frequent contractions with no relaxation, and an inability to feel or engage the fetal presenting part. Management involves preventative measures and early detection of potential obstructions, as well as curative measures like caesarean section to immediately terminate labour and prevent complications like rupture of the uterus.