While breathing a certain way may seem simplistic, and perhaps even irrelevant to conditions such as pelvic organ prolapse, it is in fact true that natural breathing while under the forces of gravity is what creates and maintains the pelvic organ support system.
Conventional culture teaches that the rib cage should expand out to the sides with each in-breath. However, the lower ribs can only expand laterally when the upper abdominal wall is held in. Western women like the look of a small waist, so they cultivate a small midriff by habitually holding in their upper abdominal wall. It is not surprising therefore, that the type of breathing that supports a small waist is generally considered ‘natural’ by yoga and physical therapy. Reversal of natural breathing is the single most important factor in loss of pelvic organ support.
All healthy babies and young children breathe naturally. The intrinsic mechanism and movement of breathing involve the entire spine and ribcage, and therefore create the shape of the whole body.
On the in-breath the respiratory diaphragm moves down, while the lower rib cage rotates forward. Concurrently the stomach, liver, and loops of small bowel are pushed forward against the upper abdominal wall.
With this movement of the diaphragm, the upper rib cage also rotates forward, which is completely different than the shoulder girdle lifting up and the ribs expanding sideways. The shoulders are pulled slightly down, and the chin is drawn in and down with every breath. 
If it weren’t so, the childhood midriff would be sucked in and the shoulders rounded forward.
Watching how the configuration of the female body changes as a result of chronically holding in the upper abdominal wall, and therefore reversing natural breathing, is a fascinating study in postural degeneration.
Subtle, yet ultimately drastic and detrimental changes occur in the alignment of the head and neck, as well as the expansion of the lower abdomen. The head is held forward of the body, the chin is lifted, and the neck assumes a less vertical orientation.
As time goes by, the neck becomes more and more horizontal, as if reverting to its quadrupedal form. This is a problem for many systems in the body, not the least of which are the vertebral arteries at the base of the skull, which are subject to stroke from being abnormally compressed.
Years of contracting the upper abdominal wall forces the abdominal organs down into the pelvis, which in turn pushes the pelvic organs away from their normal positions against the lower abdominal wall.
We see this posture in yoga teachers, physical therapists, and virtually every woman in the public spotlight. Young women are admired for their tiny waists, yet it is completely lost on modern culture that cinching in the upper abdomen sets women up for many diseases later in life, including prolapse, incontinence, and chronic back, hip, and knee pain.
Returning to natural posture begins with natural breathing, which is simply a matter of allowing the midriff to come fully forward on the in-breath, and fall passively back on the out-breath.
By supporting natural breathing with Whole Woman posture, we begin to move the abdominal and pelvic organs toward their natural positions, which is the only reasonable response to these very common conditions of civilization.
