Prolonged labor usually occurs due to these two reasons:
1) a ”lazy uterus”, i.e. an uterus whose muscles do not contract hard enough or properly;
2) dirorders in normal birth that occur due to disproportion, i.e. when the head of the fetus is too large for the birth canal, or because of an abnormal position of the fetus when the position of the fetus complicates birth.
The ”lazy uterus” can be stimulated by an intravenous infusion of certain hormones into the bloodstream (see labor induction). In some cases of prolonged labor, delivery will have to be performed with a caesarean section or forceps, which depends on the expected birth date and position of the fetus in the uterus.