The question of whether a man experiences greater pain than a woman when passing a kidney stone is a common query. Kidney stones (renal calculi or nephrolithiasis) are hard, crystalline mineral deposits that form inside the kidney due to an imbalance of substances in the urine. These stones cause intense discomfort as they exit the body through the narrow passages of the urinary tract. Exploring the biological factors, including the physiological cause of the pain and structural differences in the body’s plumbing, offers a clearer understanding of the varied experiences.
The Mechanism of Kidney Stone Pain
The intense physical suffering associated with a kidney stone, known as renal colic, stems from a physiological response identical in both sexes. This severe, spasmodic pain is caused by the obstruction the stone creates, not by the stone scraping the tract walls. When a stone dislodges from the kidney and enters the ureter—the narrow tube connecting the kidney to the bladder—it blocks the normal flow of urine.
This blockage causes urine to back up, rapidly increasing pressure within the kidney’s collecting system, a condition called hydronephrosis. The resulting distension stretches the renal capsule, the fibrous covering around the kidney that contains pain-sensing nerves. This stretching is the initial source of the deep, aching flank pain commonly reported.
As the body attempts to dislodge the obstruction, the muscular walls of the ureter contract intensely in involuntary spasms to push the stone toward the bladder. These powerful, peristaltic waves cause the sharp, fluctuating pain that radiates from the flank toward the lower abdomen and groin. The intensity of this pain is directly proportional to the degree of obstruction and resulting pressure, a mechanism that operates the same way regardless of sex. The sheer power of these ureteral muscle contractions and the rapid pressure buildup are what make renal colic one of the most severe forms of acute pain a person can endure.
Anatomical Differences Impacting Stone Passage
While the source of renal colic is universal, the anatomy of the lower urinary tract presents structural variations that influence the final stage of stone passage. The ureters are similar in length and diameter for both sexes, and both have three common points of narrowing where a stone is likely to become lodged.
Differences become pronounced as the stone travels into the urethra, the final exit tube. In men, the urethra is notably longer, averaging 15 to 22 centimeters, and passes through the prostate gland and the entire length of the penis. This extended passage involves several curves and constrictions that prolong the final stage of the painful process.
Conversely, the female urethra is significantly shorter, typically measuring only 3 to 6 centimeters, and is relatively straight. Once the stone exits the bladder, it has a much shorter distance to travel to exit the body. The female pelvic anatomy also differs in the course the ureter takes, passing close to the cervix, which can affect the stone’s trajectory and the location of pain referral.
Why Pain Perception and Severity Differ
The perceived difference in pain severity between men and women involves anatomical factors, pain referral patterns, and biological processing. For men, the final moments of stone passage often involve severe discomfort radiating into the testicle and scrotum. This phenomenon is caused by the shared nerve pathways between the kidney/ureter and the groin area. This specific pain pattern, combined with the stone’s journey through the longer, more complex male urethra, contributes to the overall perception of prolonged suffering.
Women frequently report pain localized to the pelvis or lower abdomen, sometimes mimicking gynecological symptoms. This difference in pain radiation can occasionally lead to a misdiagnosis or a delay in treatment. While the shorter female urethra may reduce the time spent in the final stage of passage, it does not negate the intense renal colic experienced in the ureter.
Biological differences in pain processing and hormonal influences also affect the subjective experience. Estrogen, for example, affects pain thresholds. Studies comparing renal colic to other forms of severe pain, such as childbirth, show that many men describe a kidney stone as the single worst pain they have ever felt. A substantial number of women who have experienced both report that renal colic was equally or more excruciating than labor, underscoring the extreme nature of the condition for everyone.