Urinary incontinence is a common and distressing pregnancy and postpartum problem. It is usually urinary stress incontinence. Stress incontinence happens when the bladder sphincter muscle does not function well enough to hold in urine in the bladder.
Recently I was called for a delivery. I arrived to find there was blood in the urinary catheter. The catheter had been inserted as the patient had an epidural block. I checked and found the blown-up balloon of the catheter was in her urethra. I deflated the balloon, removed the catheter and she went on to have a spontaneous vaginal delivery. I inserted a new catheter into her bladder after delivery, which remained in situ until after the epidural had worn off. A catheter is essential with an epidural as otherwise, it is likely bladder will become overdistended with urine and that will cause bladder function damage. She had a quick labour of one and hours duration with minimal pushing needed in the second stage.
When I saw her the next day she said she was incontinent. She said every time she stood up urine ran down her leg. I advised her that the balloon coming through her bladder neck would have stretched the bladder neck and this temporarily would have made the problem worse. But as well there must be a weakness of her bladder neck muscle to allow the catheter balloon to descend into her urethra.
I encouraged her to conscientiously do pelvic floor exercises. She was not overweight, so excess weight was not contributing issue. Three weeks later she told me she had very conscientiously been doing Kegel pelvic floor exercises and was pleased to report that the incontinence had gone.
Cause of stress incontinence
Stress incontinence is due to weakness of the sphincter muscle of the bladder neck. The bladder sphincter is a muscular valve that lies at the bottom of the bladder. It works to keep a woman continent and control the flow of urine out of the bladder. In pregnancy, the expanding uterus puts pressure on the bladder neck. If the muscles in the bladder sphincter are intrinsically weak then in pregnancy urine will leak out of the bladder, especially in advanced pregnancy and when there is additional pressure exerted e.g. coughing or sneezing, running or jumping.
While there is not the gravid uterus postnatally, there is still a large uterus (to level of umbilicus) immediately postpartum putting pressure on the bladder sphincter. As well, if there has been a vaginal delivery, there will be weakened muscles in the pelvic floor (which can cause an overactive bladder). Sometimes there is displacement of the bladder neck with pelvic floor stretching which will affect the way the bladder sphincter muscle opens and closes.
- It is reported 10 – 15 % of women have urinary incontinence before they have an ongoing pregnancy.
- In pregnancy. Studies have reported over 50% of pregnant women, especially in the third trimester, have urinary incontinence.
- The reported incidence of postpartum incontinence varies between studies but certainly would be a problem for at least 30 % or women after delivery. The reported incidence of postpartum incontinence in one large recent self-reporting study of 14,335 women was 45.4%. Some studies report over 50 % incidence.
- Family history. Family history studies have found a two-fold to three-fold greater prevalence of stress incontinence among first-degree relatives of women with stress incontinence compared to first-degree relatives of continent women. The risk was somewhat higher for sisters of a woman with incontinence than for her daughters. A recent large American study of postmenopausal sisters – where one sister had at least one ongoing pregnancy and the other sister had never had an ongoing pregnancy. The study found the incidence of incontinence was similar between sisters, concluding that pregnancy and childbirth were not the determinant of incontinence likelihood in later life but rather genetics.
- Weight. One article, that has considered many studies, reported maternal weight is an important risk factor and there was an 8% increased risk of urinary incontinence per BMI (body mass index) unit increase. This increase was the same be it a vaginal or Caesarean section delivery. Other studies have also reported obesity is an important factor. To lose weight, if overweight, is very important in the management of stress incontinence.
- Enuresis. Studies have found that if there has been bedwetting as a child there is higher likelihood of incontinence in pregnancy and postnatally.
- Age. Likelihood of incontinence increased with increasing age. Age is reported to be a significant risk factor for incontinence in pregnancy were the maternal age is ≥35 years.
- Pregnancy. Pregnancy in itself, independent of labour and delivery, seems to be a risk factor for postpartum incontinence, especially if the incontinence started during the first trimester. During pregnancy, the prevalence of incontinence increases with gestational age so that in one study more than half of all women report incontinence during the third trimester.
- Parity. While the first delivery is considered to increase the prevalence of incontinence the most, recent studies have demonstrated a further increase for each delivery.
- Vaginal delivery. Women who have a Caesarean section delivery have a lower incidence of postnatal incontinence. One study reported there is 30% less likely than after a vaginal delivery. Another reports the risk of developing incontinence was 71% higher after vaginal delivery than after Caesarean section delivery. While studies have reported a greater ‘protective factor’ of Caesarean sections, in all studies there is still a cohort of women who have stress incontinence after a Caesarean section delivery. Studies do not recommend a woman has a Caesarean section because of the increased risk of incontinence after a vaginal delivery.
Studies have found a higher incidence of urinary incontinence after a forceps delivery than after spontaneous vaginal delivery. As well the incontinence is more likely to persist.
Studies have not found a higher incidence of incontinence after a vacuum delivery than after spontaneous vaginal delivery.
Note these risk factors compound. So, if you have multiple risk factors you have a greater risk of urinary incontinence.
Studies found neither the duration of the second stage of labour, the baby’s head circumference or its birth weight were associated with the incidence of urinary incontinence.
What can be done to minimise the likelihood of incontinence?
Prepregnancy and pregnancy measures are especially relevant in you are in an ‘at risk’ group for urinary incontinence and if you have urinary incontinence before conceiving.
- Prepregnancy. If you are overweight, then lose weight. Participate in exercises that focus on pelvic floor muscles such as Pilates.
- Pregnancy. Pelvic floor (also called Kegel) exercises should be done conscientiously, especially as pregnancy advances. Don’t put on excess weight in pregnancy. The usual pregnancy weight gain is 10 – 12 Kg.
- After delivery. Pelvic floor (also called Kegel) exercises and losing weight if overweight has been found to reduce the severity and duration of urinary incontinence. This is true for all postnatal patients but the need for both is greater for women in the ‘at risk’ group.
The prevalence of urinary incontinence diminishes in the months after delivery. The high occurrence and rapid decline in incidence during the first 3 months following childbirth suggest that usually, incontinence is part of a normal pregnancy and delivery.
Studies that have correlated mode of delivery to stress urinary incontinence three years after pregnancy have not found a significant correlation between mode of delivery and stress incontinence. The incidence is the same, be it a Caesarean section or a vaginal delivery.
Antenatal incontinence increases the risk of postpartum incontinence, which in turn increases the risk of long-term persistent incontinence.