Postpartum stress incontinence

STRESS INCONTINENCE

Postpartum stress incontinence Katharine Robb Philip Toozs-Hobson

The arrival of a newborn baby can be one of life’s most stressful events. Stress incontinence is an unwelcome addition to a whole host of new experiences. Some women experience stress incontinence during pregnancy but prevalence varies dramatically between studies, as illustrated in Figure 1. Variations may be due to different populations studied and different methodologies. One study involving questionnaires, examinations and urodynamic investigations found that nocturia, frequency, dysuria, urgency and stress incontinence were significantly more common during pregnancy.3 In addition, 18% of patients had a urinary tract infection and 9% had asymptomatic bacteriuria. Twelve per cent had urodynamic stress incontinence during pregnancy and none after pregnancy. An overactive bladder was demonstrated in 23% of patients in pregnancy and 15% after pregnancy. The following cystometric parameters were significantly decreased during pregnancy: • volume at which a strong desire to void was experienced • volume at which urgency was experienced • maximum cystometric capacity • maximum and average flow rates.3 Even more important than prevalence of symptoms is the impact on quality of life. Antenatally, 54.3% experience an impact on quality of life and 71.1% postnatally.13 This may not, however, be entirely due to incontinence since other causes of morbidity, such as postnatal depression and loss of sleep may contribute to the deterioration in general and personal health.

Aetiology Postnatal stress incontinence may occur because of a combination of physiological and anatomical changes to the body during pregnancy and childbirth, combined with pre-existing risk factors such as connective tissue characteristics and hereditary factors. The problem may also be compounded by an increased incidence of bladder overactivity resulting in mixed incontinence.1

Katharine Robb is a research fellow in urogynaecology at Birmingham Women’s Hospital. She graduated from The Queen’s University of Belfast and is midway through a Northern Deanery Specialist Registrar rotation in Obstetrics and Gynaecology. Philip Toozs-Hobson is the lead clinician in urogynaecology at Birmingham Women’s Hospital. He trained to practise tertiary urogynaecology at King’s College Hospital and his MD thesis was into changes in the female pelvis after childbirth.

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Prevalence of stress urinary incontinence before, during and after pregnancy Study

% of women with stress incontinence before pregnancy

during pregnancy

after pregnancy

Meyer et al.

–

31

7

Logan et al.2

17

56

40

Nel et al.

–

12

–

Dolan et al.

–

55

26

Rockner et al.5

–

–

36

1

3 4

1

Pregnancy Figure 2 illustrates the factors present during pregnancy which, in combination, contribute to the development of stress incontinence. Connective tissue changes occur throughout the body during pregnancy. The uterine collagen and elastin content increase sevenfold and fivefold respectively, and the muscle cells hypertrophy. Animal studies have demonstrated collagen changes in knee ligaments and tendons.8 Connective tissues have been shown to be affected by corticosteroids, thyroid hormones, testosterone, oestrogen, progesterone and relaxin.8 The effect of hormones on connective tissue is further demonstrated by the observation that oestrogen replacement therapy in postmenopausal women leads to an increase in thickness and collagen content of the skin.

significantly greater following spontaneous and forceps deliveries, with reduced bladder neck elevation when performing a pelvic floor contraction. Changes were also seen on urodynamic investigation. Maximum urethral closure pressure (MUCP) was expected to fall following delivery, but this was not seen, and intra-vaginal and intra-anal pressures decreased following vaginal deliveries.1 The use of an episiotomy has not been shown to influence the development of urinary incontinence.5 Caesarean section is associated with a reduction in pelvic-floor damage compared to vaginal delivery. The increasing caesarean section rate, however, would be expected to result in a fall in the rate of stress incontinence in the population but this has not been observed. Nine per cent of women delivered by caesarean section have permanent stress incontinence which started during pregnancy.7 Physiological studies have demonstrated an increase in MUCP when standing, in those who had undergone a caesarean section. Functional urethral length was reduced following caesarean section as for vaginal delivery, but intra-vaginal and intra-anal pressures did not decrease.1 The risks of caesarean section need to be balanced against its potential benefits, including the risk of subsequent development

Mode of delivery Vaginal delivery can contribute to the development of stress incontinence in several different ways (Figure 3). One study has shown ultrasonographically that the position and mobility of the bladder neck change after delivery.1 It was found that in women who had undergone a forceps delivery, the bladder neck was lower in the standing position. Bladder neck mobility was

Possible causes of stress incontinence developing during pregnancy Altered anatomical relationship between gravid uterus and bladder

Increased urine excretion secondary to increase of glomerular filtration rate

Decreased fascial strength

Stress incontinence during pregnancy

Previous pregnancies

Concurrent disease

Congenital pelvic-floor weakness

Obesity

2

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Possible contributions of vaginal delivery to stress incontinence

... integrity of urethral sphincter

Pregnancy

Vaginal delivery

Stretching of pelvic tissues

Disruption to ...

... well-anchored bladder neck

Stress incontinence

... innervations of urethral sphincter and bladder neck

Tissue remodelling

3

Another study did not find any significant differences between those who were continent and those who were incontinent, with respect to infant weight, mode of delivery, head position or duration of labour.6 They did find that those women who were incontinent during and after pregnancy had these problems in their first pregnancy.

of de novo detrusor overactivity secondary to surgery and the risk of subsequent deliveries. Epidural analgesia Epidural analgesia in labour may affect the bladder by suppressing bladder sensation, thus delaying normal voiding, which can result in urinary retention. Caudal analgesia can also cause a similar phenomenon. Patients with epidurals may also have an increased risk of an operative delivery which may in turn have effects on the pelvic floor. Attention to bladder care in labour is important to prevent overfilling. The results of various studies investigating the relationship between epidural analgesia and stress incontinence are shown in Figure 4, but the effect of changes in anaesthetic techniques must be considered when interpreting the literature.

Predisposition to incontinence It has been suggested that pregnancy may reveal incontinence in women who are destined to develop it in later life anyway.8 One study demonstrated that the mothers of patients with stress incontinence were five times more likely to have had stress incontinence than mothers of a control group, suggesting some hereditary component.6 Biopsies of nulliparous women show that the quantity and composition of collagen differs between those with and without stress incontinence.11

Infant weight and length of labour In one study a correlation was sought between infant weight, length of the second stage of labour and urodynamic findings. The only significant correlations were between infant weight and decreases in anal pressure, and between maximum urethral pressure at stress in the standing position and the infant head circumference.1

Prevention Even if muscle tone is maintained, the changes in the supporting pelvic fascia may predispose the mother to incontinence during

Association between epidural analgesia in labour and development of stress incontinence Study

Outcome measure

Results

Meyer et al.1

Prevalence of stress incontinence Prolapse and pelvic-floor power on examination Mean urethral closure pressure Intra-vaginal/intra-anal pressures

No significant difference in any of the outcome measures between those who had epidurals and those who did not

Weil et al.9

Maximum cystometric capacity 2 to 5 days after delivery

656 ml in those who did not have epidurals 770 ml in those who did have epidurals

Viktrup et al.10

Prevalence of stress incontinence

27% of those who had an epidural 13% of those who did not have an epidural

4

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pregnancy. While many women will regain their continence completely, some factors may make continuing or recurrence of incontinence more likely. Such factors include: • altered connective tissue composition • hereditary factors • successive pregnancies • short pregnancy intervals • stretching of tissues beyond physiological limits during delivery.8 A prophylactic caesarean section will not guarantee prevention of postpartum stress incontinence because of other pregnancy effects as already discussed, particularly in higher-order pregnancies.

REFERENCES 1 Meyer S, Schreyer A, De Grandi P, Hohlfeld P. The effects of birth on urinary continence mechanisms and other pelvic-floor characteristics. Obstet Gynecol 1998; 92(4): 613–18. 2 Logan K. Audit of advice provided on pelvic floor exercises. Professional Nurse 2001; 16(9): 1369–73. 3 Nel J T, Diedericks A, Jobert G, Arndt K. A prospective clinical and urodynamic study of bladder dysfunction during and after pregnancy. Int Urogynecol J Pelvic Floor Dysfunct 2001; 12(1): 21–6. 4 Dolan L M, Hosker G L, Mallett V T, Allen R E, Smith A R B. Stress incontinence and pelvic floor neuropathy 15 years after the first delivery. BJOG 2003; 110: 1107–14. 5 Rockner G. Urinary incontinence after perineal trauma at childbirth. Scand J Caring Sci 1990; 4(4): 169–72. 6 Iosif S. Stress incontinence during pregnancy and in puerperium. Int J Gynecol Obstet 1981; 19(1): 13–20. 7 Iosif S, Ingemarsson I. Prevalence of stress incontinence among women delivered by elective caesarean section. Int J Gynaecol Obstet 1982; 20(2): 87–9. 8 Landon C R, Crofts C E, Smith A R B, Trowbridge E A. Mechanical properties of fascia during pregnancy: a possible factor in the development of stress incontinence of urine. Contemp Rev Obstet Gynaecol 1990; 2: 40–6. 9 Weil A, Reyes H, Rottenberg R D, Beguin F, Herrmann W L. Effect of lumbar epidural analgesia on lower urinary tract function in the immediate postpartum period. Br J Obstet Gynaecol 1983; 90(5): 428–32. 10 Viktrup L, Lose G. Epidural anesthesia during labor and stress incontinence after delivery. Obstet Gynecol 1993; 82(6): 984–6. 11 Keane D P, Sims T J, Abrams P, Bailey A J. Analysis of collagen status in premenopausal nulliparous women with genuine stress incontinence. Br J Obstet Gynaecol 1997; 104(9): 994–8. 12 Morkved S, Bø K. Effect of postpartum pelvic floor muscle training in prevention and treatment of urinary incontinence: a one-year follow up. Br J Obstet Gynaecol 2000; 107: 1022–8. 13 Dolan L M, Walsh D, Hamilton S, Marshall K, Thompson K, Ashe R G. A study of quality of life in primigravidae with urinary incontinence. Int Urogynecol J Pelvic Floor Dysfunct 2004; 15(3): 160–4.

Management Women may not seek help until symptoms are severe. They may feel embarrassed about the problem or feel that there is nothing that can be done: a questionnaire revealed that over 60% of women with leakage had not sought help.1 Postnatal pelvic-floor exercises (see pages 29–30) may increase the strength and function of the pelvic-floor musculature and reduce symptoms of urinary incontinence. It has been found that there are many barriers to women receiving pelvic-floor education, including: • lack of time • early hospital discharge • lack of knowledge and training • poor-quality leaflets which are not individualized. Many women are unable to locate and contract the pelvic-floor muscles following verbal or written advice, so healthcare support is important in ensuring the exercises are performed correctly. Supervised exercise programmes have been shown to be more efficacious than unsupervised programmes.12 It is therefore important that healthcare workers – including midwives, health visitors, general practitioners and obstetricians – who come into contact with women during their postnatal period are aware of the significant and common problem of stress incontinence, so that they can offer appropriate advice or referral to a specialized women’s physiotherapist or urogynaecology out-patient service. Duloxetine hydrochloride is a new medication which is specifically designed to manage stress incontinence by increasing urethral sphincter closure pressure (see page 33). It may be useful for women who wish to avoid surgery when they have a new baby, although it is not licensed for use in pregnant or breastfeeding women, and can be used as an adjunct to pelvic-floor exercises to give an immediate effect. If, for some women, troublesome stress incontinence persists despite pelvic-floor exercises and medication, these women should be investigated and treated. Urodynamic studies should be carried out prior to performing colposuspension or tension-free vaginal tape procedures (see pages 34–37) to confirm the presence of stress incontinence and exclude detrusor overactivity. Data on tension-free vaginal tape operations are available only to 8 years and this must be explained when counselling women about their treatment options. Future advice and planning for subsequent pregnancies must be carefully discussed and individualized. 

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