context: During pregnancy, many women experience at least some degree of urinary incontinence, which is the involuntary loss of urine. The incontinence may be mild and infrequent for some pregnant women. But it can be more severe for others. Age and body mass index are risk factors for pregnancy incontinence, according to one study. Incontinence can continue after pregnancy and may not be present right after childbirth. Some women do not have bladder problems until they reach their 40s. The kind of incontinence experienced during pregnancy is usually stress incontinence ( SI). Stress incontinence is the loss of urine caused by increased pressure on the bladder. In stress incontinence, the bladder sphincter does not function well enough to hold in urine. Urinary incontinence during pregnancy can also be the result of an overactive bladder. Women who have an overactive bladder ( OAB) need to urinate more than usual because their bladders have uncontrollable spasms. In addition, the muscles surrounding the urethra -- the tube through which urine passes from the bladder -- can be affected. These muscles are meant to prevent urine from leaving the body, but they may be "overridden" if the bladder has a strong contraction. The bladder sphincter is a muscular valve that lies at the bottom of the bladder. It works to control the flow of urine. In pregnancy, the expanding uterus puts pressure on the bladder. The muscles in the bladder sphincter and in the pelvic floor can be overwhelmed by the extra stress or pressure on the bladder. Urine may leak out of the bladder when there is additional pressure exerted -- for example, when a pregnant woman coughs or sneezes. After pregnancy, incontinence problems may continue, because childbirth weakens the pelvic floor muscles, which can cause an overactive bladder. Pregnancy and childbirth also may contribute to bladder control problems because of the following conditions: Damage to the nerves that control the bladder The fact that the urethra and bladder have moved during pregnancy An episiotomy, a cut made in the pelvic floor muscle during delivery of a baby to allow the fetus to come out more easily Behavioral methods such as timed voiding and bladder training can be helpful in treating urinary incontinence during and after pregnancy. These techniques are often used first and can be done at home. The changes in habits that behavioral methods involve do not have serious side effects. To practice timed voiding, you use a chart or diary to record the times that you urinate and when you leak urine. This will give you an idea of your leakage "patterns" so that you can avoid leaking in the future by going to the bathroom at those times. In bladder training, you "stretch out" the intervals at which you go to the bathroom by waiting a little longer before you go. For instance, to start, you can plan to go to the bathroom once an hour. You follow this pattern for a period of time. Then you change the schedule to going to the bathroom every 90 minutes. Eventually you change it to every two hours and continue to lengthen the time until you are up to three or four hours between bathroom visits. Another method is to try to postpone a visit to the bathroom for 15 minutes with the first urge. Do this for two weeks and then increase the amount of time to 30 minutes and so on. In certain cases, a woman may use a pessary, a device to block the urethra or to strengthen the pelvic muscles. In addition, medications also can be helpful in controlling muscle spasms in the bladder or strengthening the muscles in the urethra. Some drugs can help to relax an overactive bladder. Kegel exercises are another method that can be used to help control urinary incontinence. These exercises help tighten and strengthen the muscles in the pelvic floor. Strengthening the pelvic floor muscles can improve the function of the urethra and rectal sphincter. One way to find the Kegel muscles is to sit on the toilet and begin urinating. Then stop urinating mid-stream. The muscles that you use to stop the flow of urine are the Kegel muscles. Another way to help locate the Kegel muscles is to insert a finger into the vagina and try to make the muscles around your finger tighter. To perform Kegel exercises, you should: Keep your abdominal, thigh, and buttocks muscles relaxed. Tighten the pelvic floor muscles. Hold the muscles until you count to 10. Relax the pelvic floor muscles until you count to 10. Do 10 Kegel exercises in the morning, afternoon, and at night. They can be done anytime -- while driving or sitting at your desk. Women who do Kegel exercises tend to see results in four to six weeks. Talk to your doctor if you still have bladder problems six weeks after delivery. Accidental leaking of urine may mean that you have another medical condition. The loss of bladder control should be treated or it can become a long-term problem.