A common cause of prolonged labor is inadequate uterine contractions, which fail to produce sufficient force to dilate the cervix and advance the fetus through the birth canal. This results in a delay or arrest of labor progress. Effective contractions are essential for cervical effacement, dilation, and fetal descent. Other factors may contribute, but insufficient myometrial activity remains the primary mechanical cause. Management often includes augmentation with oxytocin to enhance contraction strength and frequency.

Reference: Williams Obstetrics, Cunningham et al., 26th Edition.