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.
What Types of Incontinence Are Experienced During and After Pregnancy?
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