A 36-year-old woman came to the hospital six weeks after her second cesarean delivery with a swollen abdomen. Her pelvic examination was normal. Ultrasound showed free fluid across her belly but no mass and no dilated kidney. Her blood work was unremarkable, including normal urea and creatinine.
Doctors put a needle in under ultrasound guidance and drew off clear fluid. The creatinine in it came back at 9.5 mg/dL.
That number is the whole story. Creatinine in ordinary abdominal fluid tracks closely with blood levels, where the upper end of normal sits around 1.5 mg/dL. A value several times higher indicates that the fluid is not serum leaking from blood vessels. It is urine, and it is coming from somewhere it shouldn't be.
Two Injuries Nobody Saw Happen
The case appears alongside two others in a report published in April 2025 in the journal Pelviperineology by Ömer Doğukan Saraç, Erhan Hüseyin Cömert, and Eray Çalışkan, working in Kocaeli and Istanbul, Türkiye. All three women had developed a vesico-peritoneal fistula, an abnormal channel between the bladder and the abdominal cavity.
In the first woman, intravenous pyelography showed contrast leaking from the left posterior bladder wall. Cystoscopy traced the tract to the left side of the uterine incision. Only after surgeons contacted her obstetrician did the cause surface: during the delivery, bleeding vessels between the bladder and vaginal wall had been sealed with electrocautery on that exact spot. Nobody had recorded a bladder injury, because at the time there had not appeared to be one. The heat damage became apparent weeks later.
The second patient was 28, four weeks past her third cesarean for placenta previa and placenta accreta spectrum. She arrived with distension, fever and clear fluid leaking from her cervix. Her abdominal fluid carried a creatinine of 16 mg/dL. Cystography found two separate fistula tracts, one running to the uterine incision and one toward the pelvic peritoneum near the round ligament.
The third, a 32-year-old, had a bladder injury that was recognized and repaired during her cesarean a month earlier. It failed anyway. Her abdominal fluid creatinine was 12 mg/dL, compared with a blood creatinine of 2.19 mg/dL.
How Often Does Cesarean Delivery Injure the Bladder
The underlying event is uncommon but not rare enough to ignore. The authors cite cohort data putting bladder injury at 0.18% of all cesarean deliveries, roughly 0.2% for a first cesarean and 0.6% for a repeat procedure. When injury occurs, the dome of the bladder is the site in about 94% of cases.
Risk climbs with surgical history. Published estimates place the odds of bladder injury about 4.3 times higher in repeat cesarean delivery and about 2.2 times higher when placenta previa is present. All three women here had repeat cesareans, and one had placenta previa. Notably, all three were elective procedures without cervical dilatation, even though emergency delivery and advanced dilatation are the established risk factors. A separate case-control study found that women with bladder injury were far more likely to have had a previous cesarean than controls.
A systematic review and meta-analysis of iatrogenic bladder injury in gynecologic and obstetric surgery reported that about 90% of injuries are recognized during the operation, with complications after repair in roughly 1%. That leaves a small group in which nothing is spotted, and a smaller group in which a repaired injury comes apart later.
The presentation is what makes this hard. Fistulas between the bladder and the vagina or uterus announce themselves through urine leaking from the vagina. A fistula into the abdominal cavity has no exit. The urine simply pools, and the woman notices her abdomen swelling.
Cesarean delivery is among the most commonly performed operations in the world, and bladder injury has been described in the surgical literature as an obstetrician's nightmare precisely because scar tissue from earlier procedures makes the dissection unpredictable. Injuries often occur while creating the bladder flap over the lower uterine segment, or while trying to stop bleeding. Urine escaping into the abdominal cavity after a cesarean has been reported before, including a documented case of uroperitoneum following the procedure, but the fistula version remains uncommon enough that most obstetricians will never see one.
What Recovery Actually Required
None of these three cases were resolved with drainage alone. Each woman underwent cystoscopy, excision of the fistula tract, excision of the bladder defect, and multilayered bladder repair reinforced with an omental flap, tissue borrowed from the fatty apron that hangs over the intestines and used here as a biological patch between the bladder and uterus.
In two cases, surgeons confirmed the repair by filling the bladder with diluted methylene blue and observing for leaks. Catheter drainage was followed for 10 to 14 days. All three recovered without further problems, and one had a follow-up cystogram confirming the bladder was intact.
Timing was consistent. All three presented between 28 and 42 days after their operations; all had abdominal distension obvious enough to be identified as free fluid on ultrasound, and only one had a fever.
The authors' recommendation is narrow: consider a vesico-peritoneal fistula when a woman develops abdominal distension with ascites within several months of a cesarean, and check the creatinine in that fluid. This is a three-patient report from a single group, which establishes a pattern worth recognizing rather than a measure of its frequency. Anyone with a swollen abdomen, persistent pain, or fever in the weeks after a cesarean should be evaluated promptly.
Key Questions Answered
What is a vesico-peritoneal fistula? An abnormal channel between the urinary bladder and the abdominal cavity, allowing urine to drain into the abdomen instead of out through the urethra. It is a rare complication of cesarean delivery.
Why did the abdominal fluid creatinine matter so much? Creatinine in ordinary abdominal fluid stays close to blood levels, with normal values topping out around 1.5 mg/dL. Readings of 9.5, 12, and 16 mg/dL in these patients identified the fluid as urine and pointed to a urinary tract leak.
How can a bladder injury go unnoticed during surgery? Two of these three injuries were attributed to electrocautery used to stop bleeding. Heat damage may not create a visible hole immediately, with the tissue breaking down days or weeks later.
How common is bladder injury during cesarean delivery? Published cohort data put it at about 0.18% of all cesarean deliveries, roughly 0.2% for first procedures and 0.6% for repeat ones, most often at the dome of the bladder.
Was surgery required? Yes. All three patients needed fistula excision and multilayered bladder repair with an omental flap, followed by 10 to 14 days of catheter drainage. Drainage alone did not fix the problem.
When should a woman seek care after a cesarean? Abdominal swelling, worsening pain, fever or unusual fluid leakage in the weeks following delivery all warrant prompt medical assessment.
