“After I urinate, I often feel that my bladder has not emptied completely. Sometimes after passing gas or having a bowel movement I can urinate again and feel more relieved. My urine stream may also spray or split at the beginning. What could be causing this?”
Quick Answer
Feeling that the bladder has not emptied can occur with an enlarged prostate, but BPH is not the only possible cause.
A split or spraying stream, difficulty emptying and needing to urinate again shortly afterward can also occur with urethral narrowing, bladder-neck obstruction, stones, pelvic-floor dysfunction, constipation or a bladder muscle that is not contracting effectively.
The fact that passing gas or having a bowel movement sometimes allows more urine to come out does not prove that an enlarged prostate is pressing against the rectum. Changes in abdominal pressure, constipation and pelvic-floor relaxation may influence urination.
If this happens regularly, the most useful next step is to measure how much urine remains in your bladder after you urinate and investigate why.
What Does “Unable to Empty My Bladder” Mean?
Doctors call urine left inside the bladder after urination the post-void residual, or PVR.
Some people with incomplete emptying notice:
- feeling that urine remains in the bladder
- needing to urinate again shortly afterward
- a weak stream
- starting and stopping
- straining to urinate
- dribbling after urination
- frequent urination
Chronic urinary retention can develop gradually, and some people can still pass urine even though the bladder does not empty properly.
Could an Enlarged Prostate Cause This?
Yes.
The prostate surrounds the first part of the urethra just below the bladder.
When the prostate enlarges, it can increase resistance to urine leaving the bladder.
This may cause:
- hesitancy
- weak flow
- intermittent flow
- straining
- incomplete emptying
- frequent urination
- nighttime urination
You can read more about these symptoms in my guide to BPH symptoms and urinary problems.
But symptoms alone cannot prove that BPH is the cause.
What Else Can Prevent the Bladder From Emptying?
Several conditions can interfere with urine flow or bladder contraction.
| Possible cause | How it may affect urination |
|---|---|
| Enlarged prostate | May narrow the bladder outlet and cause weak flow, hesitancy and incomplete emptying. |
| Urethral stricture | Scar-related narrowing can cause weak, narrow, split or spraying urine flow. |
| Bladder-neck obstruction | The outlet of the bladder may not open normally even without a markedly enlarged prostate. |
| Urinary stones | A stone may intermittently interfere with urine flow. |
| Constipation | A full rectum and pelvic pressure can worsen urinary symptoms in some people. |
| Tight pelvic-floor muscles | Poor relaxation during urination can make starting or completing urination difficult. |
| Underactive bladder | The bladder muscle may not contract strongly enough to empty completely. |
| Medicines | Some antihistamines, decongestants, anticholinergic drugs and other medicines can worsen retention. |
Why Can I Urinate More After Passing Gas?
This is an interesting symptom, but it should not be interpreted too literally.
The original answer suggested that gas expands the rectum, physically moves a very enlarged prostate and increases pressure on the urethra. That explanation is not established.
A more plausible explanation is that several things may change when you pass gas or have a bowel movement:
- abdominal pressure changes
- the pelvic-floor muscles may relax
- rectal fullness decreases
- you may naturally attempt to urinate again
If constipation or rectal fullness is present, urinary symptoms may temporarily feel worse.
It simply suggests that pelvic pressure, bowel function or muscle coordination may be influencing your ability to empty.
Can Constipation Affect Urination?
Yes.
A full rectum can contribute to urinary difficulty in some people, particularly when other urinary problems already exist.
Constipation is also recognized as one possible contributor to urinary retention.
For that reason, keeping bowel movements regular may help:
- eat adequate fiber
- remain physically active
- drink an appropriate amount of fluid
- avoid repeatedly delaying bowel movements
However, constipation should not automatically be blamed for persistent urinary retention.
Why Does My Urine Spray or Split?
A spraying or split stream is another reason not to assume the prostate is the only problem.
Temporary splitting can sometimes occur because the opening of the urethra briefly sticks together.
Persistent or recurrent spraying may also occur with narrowing or structural abnormalities of the urethra.
A urethral stricture is one possibility, particularly if you also have:
- weak flow
- straining
- difficulty starting
- incomplete emptying
- a consistently narrow or abnormal stream
A urologist can investigate this if the symptom continues.
Why Do I Need to Urinate Again Soon After Finishing?
This may represent what patients often call double voiding.
You urinate once, wait for a short period, and then find that more urine can be passed.
Sometimes this is simply because the bladder did not empty fully during the first attempt.
In selected patients, relaxed double voiding may help reduce residual urine, but frequently needing to do this is still a reason to find the underlying cause.
Could My Bladder Muscle Be Weak?
Yes.
An important condition called detrusor underactivity occurs when the bladder muscle does not contract strongly enough or long enough to empty effectively.
It can produce symptoms very similar to prostate obstruction:
- slow flow
- hesitancy
- straining
- interrupted urination
- incomplete emptying
Current European guidance emphasizes that a high post-void residual may result from obstruction, poor bladder-muscle function or both.
Why Is This Important Before BPH Treatment?
Because the treatment may differ.
If the problem is mainly an enlarged prostate causing obstruction, BPH treatment may improve urine flow.
If the prostate is not the main problem and the bladder muscle is weak, simply shrinking or opening the prostate may not fully restore normal emptying.
If there is a urethral stricture, that requires a different treatment strategy again.
This is why diagnosis should come before choosing treatment.
How Is Incomplete Bladder Emptying Checked?
One of the simplest tests is measurement of the post-void residual.
You urinate, and shortly afterward the amount remaining in the bladder is measured using:
- bladder ultrasound
- a portable bladder scanner
- or occasionally a urinary catheter
This provides objective evidence of whether the bladder is actually retaining urine.
What Other Tests Might Be Needed?
Depending on your history and examination, a clinician may consider:
- urinalysis
- urine culture if infection is suspected
- post-void residual measurement
- uroflowmetry
- physical and neurological examination
- prostate assessment
- ultrasound
- cystoscopy when urethral or bladder obstruction is suspected
- urodynamic testing in selected cases
See my guide to prostate and urinary tests for additional information.
What Is Uroflowmetry?
Uroflowmetry measures how quickly urine leaves the bladder and records the pattern of urine flow.
It can identify an abnormally slow or interrupted stream.
However, a slow flow by itself cannot always tell whether the cause is an obstruction or a weak bladder muscle.
That is why uroflowmetry is often interpreted together with residual urine and other findings.
Could Urodynamic Testing Help?
Sometimes.
Urodynamic testing evaluates how the bladder stores and releases urine.
In difficult cases, pressure-flow testing can help distinguish between:
- bladder outlet obstruction
- and weak bladder contraction
This can be particularly useful when symptoms are significant but the cause remains uncertain.
Does a Digital Rectal Examination Diagnose BPH?
Not by itself.
A digital rectal examination allows a clinician to feel the back surface of the prostate and assess features such as approximate size, symmetry and consistency.
The old statement that a normal prostate “cannot be touched with the finger” is incorrect.
A normal prostate is ordinarily palpable during a properly performed rectal examination.
The examination does not measure prostate volume precisely, however, so ultrasound or other imaging may be used when accurate size is important.
Can an Enlarged Prostate Press Directly on the Rectum?
Very large pelvic or prostate abnormalities can affect nearby structures, but ordinary BPH should not be explained as the prostate becoming five to seven times larger and being pushed back and forth between rigid bones and the rectum.
That is not an accurate description of pelvic anatomy.
BPH mainly causes urinary symptoms because prostate tissue around the urethral outlet increases resistance to urine flow.
Does BPH Mean Something Dangerous Is Causing the Prostate to Enlarge?
No.
The original answer implied that prostate enlargement itself may be caused by various diseases, some benign and some very dangerous.
That wording is misleading.
Benign prostatic hyperplasia is itself a noncancerous condition.
Prostate cancer and BPH can coexist, but BPH does not become prostate cancer.
If a clinician has concerns about prostate cancer, evaluation is based on age, PSA, examination, family history and other risk factors—not merely the fact that urine flow is weak.
Could Medication Be Making Emptying Worse?
Yes.
Some medicines can interfere with bladder contraction or increase resistance at the outlet.
Examples can include certain:
- cold and allergy medicines
- antihistamines
- decongestants
- anticholinergic medicines
- antidepressants
- opioid medicines
Do not stop prescription medication on your own, but bring a complete medication list to your doctor or pharmacist.
What Can I Do While Waiting for Evaluation?
If you can still urinate and do not have urgent warning signs, a few practical measures may help:
- avoid rushing or forcefully straining
- give yourself time to relax when urinating
- manage constipation
- avoid excessive caffeine and alcohol if they worsen symptoms
- review cold and allergy medicines with your pharmacist
- consider a gentle second attempt to urinate after waiting briefly
Persistent straining suggests that the underlying emptying problem should be evaluated rather than simply overcome with abdominal pressure.
When Does Incomplete Emptying Become Urgent?
- you suddenly cannot urinate at all
- your lower abdomen becomes very painful or swollen
- you develop fever or shaking chills with urinary symptoms
- you have significant visible blood in your urine
- you develop severe pain or become acutely unwell
Complete inability to urinate is called acute urinary retention and requires prompt treatment.
What I Would Recommend for Severo
Severo, I would arrange a medical or urological assessment rather than assuming that this is definitely an enlarged prostate.
I would specifically ask for an assessment of:
- post-void residual urine
- urinary flow rate
- whether there is urethral narrowing
- prostate size when clinically relevant
- constipation and pelvic-floor function
- medications that could worsen emptying
- bladder-muscle function if the cause remains uncertain
If BPH is confirmed, there are effective BPH medications and procedures available depending on severity.
Severo, the fact that you can pass more urine after passing gas or having a bowel movement is interesting, but I would not use it to diagnose prostate enlargement. Your feeling of incomplete emptying and the spraying or split stream deserve a more systematic evaluation. An enlarged prostate is one possibility, but urethral narrowing, constipation, pelvic-floor dysfunction or weak bladder contraction can cause similar symptoms. Measuring your residual urine after voiding is a simple and useful place to start.