The honest answer is that no strong evidence shows men experience more pain than women when passing a kidney stone. One study that directly measured pain severity during renal colic found no significant difference between male and female patients’ reported pain scores. The belief that men suffer more is widespread but not well supported by clinical data. What the research does reveal is a more complicated picture involving hormones, anatomy, stone characteristics, and even biases in how pain gets treated in the emergency room.
What Pain Scores Actually Show
Kidney stone pain, called renal colic, is widely regarded as one of the most intense forms of acute pain. But when researchers have tried to measure whether that pain differs by sex, the results are surprisingly flat. A study examining predictors of renal colic severity found no significant difference between men’s and women’s pain scores on a standard visual analog scale.1PubMed Central. The severity of renal colic pain: Can it be predicted? That’s worth pausing on, because it directly contradicts the common assumption that the male urinary tract makes stone passage uniquely agonizing for men.
The pain of kidney stones comes primarily from the stone lodging in or traveling through the ureter, the narrow tube connecting the kidney to the bladder. Both sexes have ureters of roughly similar diameter, and the mechanism of pain is the same: the stone causes a backup of urine, the ureter spasms around the obstruction, and pressure builds in the kidney. That process does not meaningfully differ between men and women. Where anatomy does diverge is the urethra, the final stretch from bladder to outside the body. The male urethra is substantially longer and passes through the prostate, which can make the last phase of passing a stone uncomfortable. But most kidney stone pain occurs well upstream of the urethra, in the ureter and kidney, so the urethra’s length is less relevant to the overall pain experience than people assume.
How Hormones Shift the Pain Experience
Even if the stone itself causes similar local effects in both sexes, the brain’s processing of that pain signal is not identical between men and women. A growing body of evidence points to sex hormones as a key factor in how pain is perceived. Testosterone appears to raise the pain threshold, meaning men may need a stronger stimulus before perceiving it as painful. Estrogen, on the other hand, fluctuates throughout the menstrual cycle and has been associated with increased pain intensity and perception during certain phases.2PubMed Central. The Role of Sex Hormones in Pain-Related Conditions These hormonal differences are present from puberty onward and influence pain sensitivity across many conditions, not just kidney stones.
Beyond hormones, differences in how endogenous opioids function, the body’s own pain-dampening chemicals, also appear to play a role in sex-based pain disparities.3PubMed Central. Sex differences in pain: a brief review of clinical and experimental findings Genetic variation adds another layer. What this means practically is that women may, on average, have a lower threshold for perceiving pain across many types of stimuli, not because the stimulus itself is worse but because the nervous system processes the signal differently. Whether this translates to women experiencing worse kidney stone pain in the real world is still unresolved. The study that directly measured colic pain scores found no difference, which suggests that whatever hormonal and neurological factors exist, they may not produce a detectable gap in this specific type of acute pain.
Stone Size Matters More Than Sex
If you want to predict how painful and difficult a kidney stone episode will be, the stone’s size and location in the urinary tract are far better predictors than whether the patient is male or female. A large study tracking spontaneous stone passage found that stones under 3 millimeters passed on their own about 98% of the time, while stones 5 millimeters wide passed about 65% of the time. At 6 millimeters, the rate dropped to roughly a third, and stones 6.5 millimeters or larger passed spontaneously only about 9% of the time.4PubMed. Size matters: The width and location of a ureteral stone accurately predict the chance of spontaneous passage
The practical takeaway is that a 2-millimeter stone is likely to cause a brief, manageable episode regardless of your sex, while a 7-millimeter stone is almost certainly going to require a procedure whether you’re a man or a woman. The pain experience tracks closely with stone size because larger stones cause more obstruction, more ureteral spasm, and more pressure buildup in the kidney. When people compare kidney stone stories and one person describes an excruciating multi-day ordeal while another recalls a few hours of discomfort, the difference usually comes down to how big the stone was and where it got stuck, not whether the person was male or female.
Stone Composition Differs Between the Sexes
Men and women do tend to form somewhat different types of kidney stones, and this can indirectly affect the experience. In both sexes, calcium-based stones are the most common. But as body weight increases, the proportion of uric acid stones rises more steeply in men than in women. In men with obesity, uric acid stones accounted for nearly 29% of stones compared to about 7% in normal-weight men. Women with obesity saw a rise too, from about 6% to 17%, but the shift was less dramatic.5PubMed. Influence of body size on urinary stone composition in men and women
Why does composition matter for pain? Uric acid stones can sometimes be dissolved with medications that alkalinize the urine, potentially sparing a patient from the worst of a passage episode. Calcium stones generally cannot be dissolved and either pass on their own or require intervention. The composition also affects stone shape and surface texture. Smooth stones glide through the ureter more easily than jagged ones, and certain mineral compositions tend to form rougher surfaces. So while the pain mechanism is the same regardless of stone type, the practical experience can differ based on what the stone is made of, and that varies somewhat by sex and body size.
Why Women Are Catching Up in Kidney Stone Rates
Kidney stones have historically been thought of as a “men’s disease,” and the numbers used to back that up. Men have traditionally been about twice as likely as women to develop stones. But that gap has been narrowing for years. Data from national surveys shows that the prevalence of kidney stone disease increased significantly among women between 2008 and 2018, while the rate among men did not show a significant increase over the same period.6PubMed Central. Gender Differences in Kidney Stone Disease (KSD): Findings from a Systematic Review Among working-age adults under 50, women were found to be just as likely as men to develop stones. The fastest-growing group was adolescent females.
Several risk factors specific to women have been identified, including multiple pregnancies, menopause, and the use of female hormones.6PubMed Central. Gender Differences in Kidney Stone Disease (KSD): Findings from a Systematic Review Rising rates of obesity in women, changes in diet, and possibly increasing use of certain supplements may also be contributing. The clinical significance of this shift is that kidney stones can no longer be dismissed as unlikely in female patients presenting with flank pain or abdominal symptoms, something that has historically led to delayed diagnosis in women.
Stent Pain After Procedures
When a kidney stone cannot pass on its own, urologists often place a ureteral stent, a thin tube that holds the ureter open to allow urine to drain and any remaining stone fragments to pass. Stents are effective but notoriously uncomfortable. And here the data does show a sex difference, just not the one most people expect. An international registry study found that women reported higher stent-related pain scores than men.7PubMed. Associations between ureteral stent indwelling time, patient characteristics, and stent pain from an international prospective registry
This finding aligns with the broader pain-sensitivity research suggesting that women tend to report higher pain levels across many types of medical procedures and chronic conditions. It also raises a practical concern: if women consistently experience more stent discomfort, their post-procedure management should account for that. Stent-related symptoms include bladder urgency, flank discomfort, and pain during urination, and they can persist for days or weeks depending on how long the stent stays in place. For anyone facing a stone procedure, asking about the expected duration of stent placement and what pain management options are available is worth doing before the procedure happens.
Kidney Stones in Children
Kidney stones in children and adolescents are becoming more common, and the sex differences start showing up early. In pediatric patients, girls tended to be older at presentation and more frequently reported flank pain as a symptom compared to boys, with 39% of girls describing flank pain versus 22% of boys.8PubMed Central. Comparison of Risk Factors for Pediatric Kidney Stone Formation: The Effects of Sex Whether this reflects a genuine difference in pain experience or differences in how boys and girls describe and report symptoms is hard to untangle. Girls also had higher rates of markers suggesting urinary tract infection alongside their stones, which can compound the pain experience and complicate diagnosis.
The pediatric data matters because it challenges the idea that sex differences in kidney stone pain are purely about adult anatomy or reproductive hormones. Even before puberty significantly alters the hormonal landscape, boys and girls present differently. This suggests that pain perception, symptom reporting, and possibly stone characteristics all interact from an early age.
Kidney Stones During Pregnancy
Pregnancy creates a unique and difficult situation when kidney stones occur. The ureters naturally dilate during pregnancy due to hormonal changes and pressure from the growing uterus, which means mild hydronephrosis, a backup of urine in the kidney, is actually normal in pregnant women. But when a stone causes a blockage on top of that already-stressed system, the result can be severe pain, and distinguishing stone pain from labor contractions or other pregnancy complications adds diagnostic difficulty. Conservative management with pain relief and fluids is usually the first approach. When that fails, stent placement under ultrasound guidance becomes an option, typically reserved for cases with persistent pain, progressive kidney swelling beyond 2 centimeters of pelvic dilation, or the onset of uterine contractions.9PubMed Central. Our ultrasonographic experience in the management of symptomatic hydronephrosis during pregnancy
The concern during pregnancy is not only the pain itself but the risk that untreated obstruction could trigger preterm labor or cause kidney damage. Many of the standard imaging tools used to diagnose stones, like CT scans, are avoided during pregnancy due to radiation exposure, which can delay diagnosis. Ultrasound becomes the primary imaging tool but is less sensitive for detecting small stones. This is a scenario where the pain experience is inseparable from a broader set of medical risks that simply don’t apply to men or non-pregnant women.
Bias in How Pain Gets Treated
One underappreciated aspect of the “who has it worse” question is how pain treatment itself differs by patient demographics. Research examining physician prescribing patterns for renal colic found no overall differences by patient sex in the decision to treat pain or in the maximum permitted doses of medication.10PubMed Central. Do gender and race affect decisions about pain management? That’s somewhat reassuring. But the same research uncovered significant disparities by race: male physicians prescribed higher doses of hydrocodone to white patients with renal colic than to Black patients, while female physicians showed the reverse pattern.11PubMed. The influence of gender and race on physicians’ pain management decisions
These findings highlight that the experience of kidney stone pain is shaped not only by the stone and the body it’s in but also by the clinical environment where treatment happens. A patient whose pain is undertreated will obviously suffer more, regardless of what their nerve fibers are actually signaling. While the sex-based treatment differences were not significant in these studies, the racial disparities were, and they applied specifically to kidney stone pain. For anyone navigating an ER visit for renal colic, being a clear advocate for adequate pain control matters. The clinical guidelines for acute renal colic generally recommend nonsteroidal anti-inflammatory drugs as first-line treatment, with opioids reserved for cases where NSAIDs aren’t sufficient.
What People Get Wrong About Comparing Kidney Stone Pain
The most common misconception is that men have it worse because their urethras are longer. As covered earlier, the urethra plays a minor role in kidney stone pain compared to the ureter. A related myth is that passing a kidney stone is comparable to childbirth. Many women who have experienced both will say they found the stone worse, while others say labor was harder. These comparisons are essentially meaningless from a scientific standpoint because pain is subjective, context-dependent, and not measured on a universal scale that allows cross-condition comparisons. Childbirth involves hours of progressive labor pain with hormonal support systems designed to help manage it. A kidney stone hits without warning, often in the middle of the night, with no natural coping mechanism in place. The experiences are too different in structure to rank.
Another misconception is that women’s wider pelvises somehow make stone passage easier. The pelvis is not the bottleneck. The ureter is. And ureteral diameter is similar between the sexes. If anything, the evidence on stent pain and pain perception suggests women may face a slightly harder time with certain aspects of the kidney stone experience, though the acute colic pain itself appears comparable. The most honest conclusion the science supports is that kidney stone pain is brutal for everyone and that the factors determining how bad any individual episode will be, stone size, stone location, speed of onset, and access to prompt treatment, have little to do with whether the patient is a man or a woman.