The mother has much greater ease and freedom to move spontaneously and to change position to assist the descent of the baby.
Buoyancy promotes more efficient uterine contractions and better blood circulation, resulting in better oxygenation of the uterine muscles, less pain for the mother, and more oxygen for the baby.
Immersion reduces opposition to gravity; supports the mother's weight so that her energy can be used to cope with the contractions.
As a woman relaxes deeply in water, her hormones kick in and she starts progressing faster and with more rhythm; labor becomes more efficient. Water relaxes the pelvic floor muscles.
Water minimizes pain so effectively that for most women other pain control methods are no longer needed.
Water stimulates the touch and temperature nerve fibers in the skin.
It blocks impulses from the pain fibers, known as the Gate Theory of Pain.
Immersion is often more effective and safer than an epidural. Some people call water birth an "aquadural".
Water can be an effective way to stimulate dilation of the cervix when the mother has difficulty progressing into the active stage of labor.
Water can reduce the need for drugs to artificially stimulate labor. Often, simply getting into the tub will result in dramatic and rapid progress to full dilation within an hour or two.
Lowering of blood pressure. When anxiety is causing high blood pressure, immersion in water often helps lower it.
Immersion helps relieve anxiety and promotes relaxation. Water helps a woman to let go and focus inward as labor strengthens.
Many mothers are less inhibited in the water. The warm water softens the vagina, vulva, and perineum, leading to fewer injuries to these tissues.
Many women experience rapid second stages, with the baby emerging minutes after the body starts pushing, also known as the fetus ejection reflex (see Odent, The Nature of Birth and Breastfeeding).
When a woman delivers her baby while remaining awake, aware and in control, it greatly enhances the birth experience for her and becomes a source of great personal strength and power that enriches her life forever.
Enhanced family relationships. When the mother's pain is dramatically reduced, many fathers eagerly take a more active role in the delivery, resulting in a greater family bond. When fathers are more involved it increases the possibility of a joyous birth. Both parents and child get to share a wondrous experience that can enhance their relationships with each other for the rest of their lives.