What causes decreased urinary output after a Cesarean section (C-section)?

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Last updated: April 16, 2025View editorial policy

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From the Guidelines

Decreased urinary output after a C-section should be evaluated promptly, and the urinary catheter should be removed immediately after surgery if it was placed during the procedure, as recommended by the Enhanced Recovery After Surgery (ERAS) society guidelines 1. This approach is based on evidence suggesting that urinary catheter placement during cesarean delivery does not improve surgical exposure or reduce urinary tract injuries, but rather increases the risk of urinary tract infections, urethral pain, and difficult voiding 1. Key factors to consider in the management of decreased urinary output include:

  • Monitoring urine output closely, with concern if less than 500 mL in 24 hours or no urination within 8 hours after catheter removal
  • Encouraging early ambulation to promote normal bladder function
  • Managing pain effectively with medications like ibuprofen or acetaminophen to reduce the risk of urinary retention
  • Possibly using temporary bladder drainage if urinary retention is diagnosed
  • Performing blood tests to check kidney function and ultrasound to assess bladder emptying if necessary It's also important to note that oliguria during surgery and anesthesia is a normal physiological response and should not automatically trigger fluid therapy; instead, the cause should be investigated before considering additional fluid therapy 1. Overall, the management of decreased urinary output after a C-section should focus on prompt evaluation, removal of the urinary catheter when appropriate, and addressing underlying causes to minimize complications and promote recovery.

From the FDA Drug Label

As with any effective diuretic, electrolyte depletion may occur during furosemide therapy, especially in patients receiving higher doses and a restricted salt intake Hypokalemia may develop with furosemide, especially with brisk diuresis, inadequate oral electrolyte intake, when cirrhosis is present, or during concomitant use of corticosteroids, ACTH, licorice in large amounts, or prolonged use of laxatives. All patients receiving furosemide therapy should be observed for these signs or symptoms of fluid or electrolyte imbalance (hyponatremia, hypochloremic alkalosis, hypokalemia, hypomagnesemia or hypocalcemia): dryness of mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, arrhythmia or gastrointestinal disturbances such as nausea and vomiting.

The use of furosemide may cause decreased urinary output (oliguria), especially if the patient experiences dehydration or electrolyte imbalance.

  • Key points to consider when using furosemide:
    • Monitor serum electrolytes and renal function
    • Avoid dehydration and electrolyte imbalance
    • Be aware of the potential for oliguria and other signs of fluid or electrolyte imbalance 2

From the Research

Decreased Urinary Output after C-Section

  • Decreased urinary output after a C-section can be caused by various factors, including postpartum urinary retention (PPUR) 3, 4.
  • Studies have shown that the incidence of PPUR after cesarean delivery can range from 24.1% to 34 confirmed cases out of a matched control group of 68 controls 3, 4.
  • Factors associated with increased risk of PPUR include:
    • Morphine-related postoperative analgesia 3
    • Multiple pregnancy 3
    • Low body mass index (BMI) 3
    • Use of postoperative intravenous and oral narcotics 4
  • Normal urine output after elective C-section has been observed to vary widely between subjects, especially after the first 6 hours, and can be affected by factors such as oxytocin infusion and blood loss 5.
  • Oxytocin infusion has been shown to reduce urine output in the first 6 hours after C-section, with a median urine output of 0.8 mL kg(-1)h(-1) compared to 1.4 mL kg(-1)h(-1) in women who did not receive oxytocin 5.
  • Other studies have focused on fluid management and prevention of hypotension after spinal anesthesia for C-section, comparing the efficacy of hydroxyethyl starch (HES) 130/0.4 to lactated Ringer's solution 6.
  • The use of HES 130/0.4 has been shown to be more effective in preventing hypotension after spinal anesthesia for C-section compared to lactated Ringer's solution 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Postpartum urinary retention after cesarean delivery.

International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics, 2007

Research

Acute urinary retention after cesarean delivery: a case-control study.

Female pelvic medicine & reconstructive surgery, 2014

Research

Normal urine output after elective caesarean section: an observational study.

International journal of obstetric anesthesia, 2010

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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