The pelvic floor muscles control the flow of urine, the voluntary contraction of the vagina, and the anal sphincter as well. The pelvic floor is composed of several layers of muscle suspended like a hammock at two points, the front and the back of the pelvis. The pressure of pregnancy increases the likelihood of the pelvic floor to sag just as a hammock does.

Healthy Pelvic Floor
A healthy pelvic floor has tone and elasticity.  However, if after childbirth these muscles are neglected, they sag below the horizontal line and with the help of gravity, continue to sag downward. Excessive sagging over a long period of time can result in serious structural changes and possible impairment of function, namely the bladder, uterus, bowel, and their contents. Common problems associated with pelvic floor weakness:

• You or your partner may feel nothing during intercourse;
• You may have difficulty retaining a tampon;
• Prolapse of the uterus. Over time, the uterus can begin to herniate through the vaginal opening, similar to the way upholstery padding protrudes through a chair when it's supportive base is defective.
• Urinary incontinence, or the involuntary escape of urine when you laugh, cough, sneeze, lift or run.

Exercise throughout your pregnancy and after is always an excellent course of action. However, because the pelvic floor is not exercised unintentionally during sports or basic physical activity, special efforts must be made to give it a workout.

Pelvic floor exercises
The pelvic floor muscles form a figure eight, as they are slung in loops around the vaginal and urethral sphincter in front and the anal sphincter at the rear. (See illustration number three.) The pelvic floor works as a coordinated whole.  Kegels, or pelvic floor exercises, involve contracting this unit as a whole.  However, our main focus is on the frontal aspect of the two sphincters -- the sphincter which controls the flow of urine and the voluntary contractions of the vagina. These exercises involve lifting up and drawing in the muscles.

Exercise #1: basic contract and release
Lay on your back, side, or front with legs apart and chest relaxed. Draw up the pelvic floor. You should feel the sides of the sphincters become tight and the inside passages become tense. Concentrate on the frontal sphincter surrounding the urethra and the vagina. Place one hand over the pubic bone and think about tightening the birth canal as high as the level of your hand.  Hold for 2 or 3 seconds and then completely relax.

Exercise #2: the elevator
Place yourself in any comfortable position.  Imagine that you are riding in an elevator. As you ascend to each floor, try to draw up the sphincter muscles a little more without losing any of the tension that you have been progressively accumulating.  Make it a smooth ride up and a smooth ride down, releasing completely at the end. Always end your pelvic floor exercises with a contraction to return the pelvic floor to its supportive resting state. Quality is more important than quantity. Do at least 50 a day during pregnancy and postpartum, and 50 a day for the rest of your life. The best part is, no one has to know you're doing them. Kegels can be done during virtually any activity.