Essential factors of labor(10) LABOR FORCE
The intermittent nature of the contractions is of great importance to both the fetus and the mother. During a contraction the circulation to the placental bed through the uterine wall is stopped; if the uterus contracted continuously the fetus would die from lack of oxygen. The intermittent allow the placental circulation to be re-established and give the mother time to recover from the fatigue effect of the contraction. The uterus is a large muscle and contractions use up a lot of energy, if continued too long this would produce maternal exhaustion.