Urinary Retention in Pregnancy and Puerperium: Acupuncture Treatment

Introduction

Urinary retention (UR) is defined as the inability to empty the bladder completely or partially. ¹ Overt UR denotes a sudden inability to pass urine spontaneously. ² Covert UR occurs when a woman passes small amounts of urine, associated with an elevated postvoid residual volume of more than 150 mL, with no symptoms of UR. ³ Postpartum voiding dysfunction is defined as failure to void spontaneously within 6 hours of vaginal delivery or catheter removal. ²

Neglected voiding dysfunction can lead to overdistension of the bladder, underactivity, prolonged voiding dysfunction with a recurrent urinary tract infection (UTI), ⁴ and urinary incontinence. ⁵ Postpartum incontinence has been linked to subsequent depression. ⁶ Persistent postpartum UR (PPUR) is defined as the inability to void spontaneously by the third day postpartum despite the use of intermittent catheterization. ⁵ Urinary frequency, voiding small amounts, a slow or intermittent stream, bladder discomfort or pain, straining to void, incomplete voiding, reduced sensation to void, and/or urinary incontinence should raise a clinical suspicion of voiding dysfunction. ⁷ PPUR can be silent because of reduced sensation and contractility due to trauma to the nerves supplying the bladder. ⁸

UR can occur at any stage of pregnancy or early postpartum period. The pathophysiology is not well-understood. Causes can be multifactorial, including physiologic, neurologic, or merchanical reasons. ³ Bladder capacity increases during pregnancy, beginning in the third month due to reduction in detrusor muscle tone. ⁹

Use of regional analgesia can cause neurologic damage leading to micturition difficulties. Detrusor function impairment can also result from overdistension of the bladder. In one report, women who received neuraxial analgesia were likely to need bladder catheterization due to larger postvoidal residual volumes. ¹⁰ Instrumental vaginal delivery, prolonged first and second stages of delivery, and labor lasting longer than 12 hours are associated with higher incidences of UR. ¹¹ Reduced uterine pressure postpartum on a hypotonic bladder can lead to incomplete emptying, and this can last for 6–8 weeks postpartum. ¹² Other risk factors are constipation and oxytocin infusion. ¹³

Reported incidences of UR vary considerably due to differences in definitions and modes of delivery. Overt UR incidence varies from 0.45% ³ to 17.9% ¹⁴ and to 37%. ⁷ Incidence of covert UR ranges from 9.7% ¹¹ to 37%. ⁸ Incidence of UR after cesarean section varies from 3.38% ¹⁵ to 11.5%. ¹²

All postpartum women should be monitored to ensure that normal bladder function returns and is maintained. Prompting women to pass urine from 4 to 6 hours postpartum, measuring the void, and using conservative methods can prevent bladder distension and subsequent voiding dysfunction. ¹⁶

Diagnosis

Abdominal palpation in pregnancy, and even in puerperium, to identify a distended bladder can be difficult. Bladder scanning by ultrasound (US) and catheterization are the preferred options. There are conflicting reports regarding the accuracy of bladder US scanning. Pallis and Wilson ¹⁷ and Blomstrand et al. ¹³ found that such scanning measured bladder size as being greater than actual bladder size, compared to the results of bladder catheterization. In contrast, Lucasse et al., ¹⁸ Yip et al. ² Nusee et al., ¹⁹ and Mulder et al. ²⁰ found bladder scans to be reasonably accurate.

Bladder catheterization is the gold standard for measuring bladder volume (Pallis and Wilson). ¹⁷ However, this procedure has risks of infection, hematuria, urethral trauma, and subsequent stricture formation. ¹¹

Prognosis

For the majority of women, normal bladder function will return usually within 4–5 days. The greater the residual volume, the more likely that they require longer periods of catheterization. Carley et al. in their study of 51 patients with overt distension, found that 45.1% had resolution by 48 hours, 29.4% by 72 hours, and 25.5% by >72 hours; in 10 patients it took 45 days. ³ Postpartum residual volumes of 700–750 mL or more had poorer prognoses (see Lim ⁷ ). In a 4-year follow-up study, Yip et al. found that there was no difference in urinary incontinence in women with or without postpartum UR. ²

Management

There is no consensus regarding the management of postpartum voiding dysfunction. ²¹ The following guidelines are usually followed. The National Institute of Healthcare and Excellence (United Kingdom) recommends that the urinary catheter should be removed once a woman is mobile after regional anesthesia, but no sooner than 12 hours after the last epidural procedure. ²² The National Institute also recommends that women who have not voided by 6 hours postpartum should be encouraged to micturate, using measures such as taking a warm bath or shower. If these measures are not immediately successful, bladder volume should be reassessed and catheterization should be considered as an urgent action. ²² The Royal College of Obstetricians and Gynaecologists (United Kingdom) recommends that no postoperative or postdelivery patients should be left more than 6 hours without voiding or catherization. ²²

UR in Chinese Medicine

In UR, irrespective of the causes, the Urinary Bladder is the diseased organ. Sinking of Spleen and Kidney Qi leads to the fetus dropping down and pressing on the bladder. The downward movement of the fetus and bladder may lead to further sinking of Spleen and Kidney Qi, producing a vicious circle. It is important for a Western medicine–trained physician to understand that, in Chinese Medicine, Spleen refers to more than the anatomical organ. Because Chinese Medicine is based on an energetic perspective, it includes Spleen Yin, Spleen Yang, Spleen Meridian, the energy behind the transportation of fluids, holding organs in their proper place, housing the intellect, raising the Qi and pensiveness. Spleen is, therefore, a whole functional unit. When Spleen Qi is Deficient, all the above functions are compromised, leading to sinking of the Uterus and Bladder, causing difficulty in voiding. Spleen Qi Deficiency is usually associated with Kidney Qi Deficiency (Sinking Qi) causing further aggravation of the problem. These are Deficiency patterns. When there is added infection in the urine, the pattern becomes Damp Heat in the Bladder, which is an Excess pattern.

Discussion

Acupuncture is quite effective for addressing UR, as shown by studies and is free from side-effects and complications.

Lauterbach et al. studied 55 patients with postpartum retention of urine. ²³ In the study's acupuncture group, 92% achieved spontaneous micturition within 1 hour following treatment. Bedside sonographic evaluation of bladder volume showed excellent correlations to actual volumes as measured by catheterization. ²³

Zhang studied 36 cases of UR using acupuncture to treat them; 30 cases were cured, 4 cases improved, and 2 cases had failures (an effective rate of 94.44%). ²⁴

Lin Hua-dong treated 130 patients with postpartum urinary retention using electroacupuncture SP 6 and SP 9 bilaterally. After 1–5 treatments, all could discharge urine successfully. ²⁵

Chen et al. reviewed 31 clinical trials (9 randomized clinical trials, 2 nonrandomized clinical trials, and 20 observational research trials). The researchers found that either the use of acupuncture alone or with herbal medicines relieved UR and achieved very high satisfaction. ²⁶

Yip et al. reported 3 studies involving 172 patients in total using acupuncture in postpartum urinary retention. ² All except 1 patient were cured with no side-effects.

Wang et al. found from 15 randomized controlled trials involving 953 patients that acupuncture alone was more effective for addressing PPUR than intramuscular neostigmine, with no adverse effects. The adverse effects associated with neostigmine were bradycardia, bronchospasm, nausea, vomiting, and increased secretions. ²⁷

Acupuncture is noninvasive. Bladder catheterization is associated with potential morbidity and sequelae. UTIs account for 17.5% of hospital-acquired infections and 80% of these are caused by urethral catheters. ²⁸ The longer the catheter is in place, the greater the risk of infection will be. For catheters left in place for more than 7–10 days, the risk of infection rises by 50%. ²⁹ Other complications include tissue trauma, blockage, encrustation, and urethral strictures, which means additional surgical procedures.

Despite the fact that acupuncture is highly effective for addressing pregnancy-related UR and is noninvasive, the evidence is still limited due to a lack of high-quality trials. A convincing demonstration of the positive effectiveness and safety of acupuncture, using studies with larger samples and high methodological quality will have positive implications for future clinical practice.

Conclusions

Acupuncture is a valuable alternative to catheterization in pregnancy-related UR due to acupuncture's high effectiveness and safety, as shown by clinical experience and studies.