Active birth is an attitude of mind. It involves acceptance and trust in the natural function and involuntary nature of the birth process, as well as an attitude or appropriate positioning of your body. An active birth could also be described as one in which the woman is empowered to give birth using her own resources and abilities. In simple terms, a person is empowered when they take control over what happens to them. When upright, the mother's body is in harmony with the downward pull of gravity.
Less effort is demanded of the uterus.
Since the uterus tilts forward during a contraction, a mother can lean forward and assist her uterus to work without resistance. When she is lying down, her uterus must work harder and less efficiently. It is easier for the baby's head to enter the mother's pelvis when she is upright, and provides the baby with the best angle of descent, in relation to gravity, through the pelvic canal. Placental circulation is improved, giving the baby a better supply of oxygen. The nerves that supply the pelvis and the uterus arise from the lower part of the spinal cord and enter through the sacrum.