Postpartum Urinary Retention

Postpartum urinary retention is inability to empty the bladder after birth. Overt retention is inability to pass urine within 6 hours of birth or after catheter removal, and covert retention is a residual volume above 150 mL in a woman who passes urine without knowing the bladder is not empty.

It occurs in 1 to 15 percent of women and results from epidural or spinal anaesthesia, perineal pain and tears, haematoma, instrumental delivery, a long second stage and bladder trauma.

It matters because overdistension damages the bladder muscle and causes infection.

• Risk factors: epidural, instrumental delivery, first labour, long second stage, perineal tears, caesarean section, large baby, opioids.
• Most recover within 24 to 72 hours with catheter drainage.
• Volumes above 500 mL carry the highest risk of long term bladder damage.

Women have a full or painful bladder above the pubis, urgency without passing urine, or frequent small voids with overflow leakage. Some have no symptoms.

• Palpable bladder.
• Small frequent voids with dribbling.
• Differential diagnosis: reduced urine output from hypovolaemia, bladder injury, urethral oedema, vulvar or vaginal haematoma, urinary fistula, neurological injury, constipation, urinary tract infection.
• Complications: bladder overdistension, infection, pyelonephritis, long term voiding dysfunction, detrusor damage, delayed mobilisation, overflow incontinence.

The approach is measurement of residual urine and a search for a cause.

• Bladder ultrasound or catheterisation after the woman has tried to pass urine; a residual volume above 150 mL confirms retention (above 500 mL is severe).
• Examination of the perineum and vagina for haematoma and tears; abdominal examination for pelvic mass.
• Urine dipstick and culture; haemoglobin; creatinine if there is flank pain.
• Neurological examination of legs, perineal sensation and anal tone if there is back pain, leg weakness or saddle numbness.

The principle is to drain the bladder at once, then allow it to recover with a planned voiding check.

• Supportive: insert a Foley catheter (14 to 16 French) and drain the full volume; leave in for 24 to 48 hours (7 days for residual volume above 1000 mL); remove the catheter in the morning and measure residual volume after the first void; privacy, upright position and warm water over the perineum; treat pain and constipation.
• Pharmacological: paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours); diclofenac 50 mg oral 8-hourly for 3 days with food if no contraindication; lactulose 15 mL oral 12-hourly; cefalexin 500 mg oral 6-hourly for 5 days or nitrofurantoin 100 mg modified release oral 12-hourly for 5 days for urinary infection; avoid opioids, anticholinergic drugs and antihistamines.
• Procedures: clean intermittent self catheterisation every 4 to 6 hours for residual volume above 150 mL after catheter removal; suprapubic catheter if urethral catheterisation fails; drainage of any compressing haematoma.
• Special groups: back pain, leg weakness or saddle numbness after epidural or spinal anaesthesia needs urgent MRI for spinal haematoma or abscess and neurosurgical review.
• Red flags: no void 6 hours after catheter removal, residual volume above 500 mL, fever above 38 degrees Celsius, haematuria, leg weakness, saddle numbness, severe perineal swelling.
• Follow-up: residual volume check before discharge; review at 1 week and 6 weeks; referral for urodynamic testing if symptoms persist beyond 6 weeks.