Ankylosing spondylitis, your vagina and urinary tract

Author: Jessica Lloyd
Senior Vulvovaginal Specialist Naturopath | BHSc(N) | ISSVD, ISSWSH, BSSM, ATMS

Last reviewed: July 20, 2026

Ankylosing spondylitis (AS) is a chronic inflammatory condition affecting the spine and joints with no known cause. AS is understood (in theory) to be an autoimmune disease and a form of reactive arthritis. There is evidence that the gut microbiome and intestinal inflammation are closely linked to this condition.

AS and bugs

While AS tends to affect men between the ages of 20 and 30, it also affects women. Symptoms range from lower back pain and stiffness through to fusing of bone, alongside a positive genetic marker. There are close associations with the microbiome, immune reactivity and inflammation, but any deciding factor or cure remains elusive. Women are more likely to experience gut symptoms than men, but gut dysbiosis with markers of inflammation was found in almost 90 per cent of a group of people with AS¹.

Various culprits have been put forward for the symptoms, including Klebsiella bacteria, which is closely linked with genitourinary tract infections. Ankylosing spondylitis is also associated with vaginal and urinary tract infections generally² and with sexual dysfunction³, and there are suggestions that infection may be the trigger for AS developing² in someone who already carries the positive genetic marker.

In plain terms: if you are positive for HLA-B27 and you get a vaginal or urinary tract infection, it could tip you into AS that wasn’t showing symptoms before.

The link isn’t new. As early as 1953, researchers were drawing associations between AS and male genitourinary infection, with observations of increased urogenital infections in male patients. Later work in women followed the same thread. Although now an old study, Lange and colleagues found genitourinary infection significantly more often in women with AS than in those without².

Understanding ankylosing spondylitis and HLA-B27

HLA-B27 is a blood test looking for a protein found on the surface of white blood cells: human leukocyte antigen B27. HLAs are immune proteins that help the body tell the difference between self and foreign substances. HLA-B27 is made from instructions in a gene passed on from our parents.

HLA-B27 may shape the gut microbiota, or alter how the antigen behaves, in some people. Subclinical gut inflammation is found in up to 60 per cent of AS patients⁷, and there is a growing association between the gut microbiome and autoimmune disease⁴.

A positive HLA-B27 test flags a higher risk of developing specific autoimmune disorders, where HLA-B27 mistakes your own cells for invading pathogens or foreign substances. The result is destruction of healthy tissue, and what’s known as spondyloarthritis. Testing positive on its own does not mean you have any of these conditions.

Spondyloarthritis is broken down into sub-groups

Ankylosing spondylitis
Crohn’s disease or ulcerative colitis-related arthritis
Psoriatic arthritis (related to psoriasis)
Reactive arthritis
Sacroiliitis (sacroiliac joint inflammation)
Uveitis (eye inflammation)

Klebsiella and AS – what’s the connection?

AS can occur after infection with Klebsiella in an HLA-B27-positive person. There appears to be molecular mimicry between HLA-B27 and Klebsiella⁵, though this theory is still developing. Increases in faecal Klebsiella have been found in European and North American patient stool samples, while antibodies to Klebsiella have been found in AS patients in England and Finland.

We still can’t say for certain that this association holds across all HLA-B27-positive people, but it does seem clear that microbes may be playing a role. Specifically, the innate immune system and gut microbes may interact in a way that drives inflammation. K. pneumoniae, a species of Klebsiella, has been implicated as at least an exacerbating agent for AS.

K. pneumoniae is surrounded by polysaccharide-rich capsules, an essential part of its virulence. In people living with AS, immune responses to specific serotypes appear to trigger higher antibody levels in HLA-B27-positive patients compared with other K. pneumoniae serotypes.

Results of studies into AS and K. pneumoniae have been conflicting, and we don’t yet know what the relationship is between K. pneumoniae antibodies and AS. We do know that antibiotic therapy has shown improvements in AS disease activity.

Ankylosing spondylitis and your vagina, vulva and urinary tract

AS is a whole-body inflammatory condition, so its effects don’t stop at your spine. Here’s where it can show up below the belt.

Urinary and genital infections: Women with AS turn up with genitourinary infections more often than women without it². The relationship may run both ways: an infection can act as a trigger in an HLA-B27-positive person, and the inflammatory state of AS may make you more prone to infections in the first place. If you get recurrent UTIs or vaginal infections and you have AS, it’s worth mentioning both to your doctor rather than treating them as separate problems.

Painful sex, or dyspareunia: In one study, women with AS scored significantly lower across every part of the Female Sexual Function Index, and had sex less often, than women without AS³. That isn’t about desire failing you. Pain, morning stiffness, fatigue, reduced hip and spine mobility, and the lower mood that often travels with chronic pain all stack up and get in the way. In the same study, women with AS who were also depressed had lower desire and arousal scores than those who weren’t.

Pelvic floor and positioning: AS commonly involves the sacroiliac joints and hips, right at the base of the pelvis. When those joints are inflamed and stiff, some sexual positions hurt, and the pelvic floor muscles can hold tension in response to pain. Guarding like this can make penetration uncomfortable and feed a pain-tension-pain loop. A pelvic health physiotherapist can be genuinely useful here, both for the muscles and for finding positions that don’t provoke your joints.

The gut-vagina angle: AS comes with gut dysbiosis and intestinal inflammation in a large share of patients, and the same levers that shift the gut microbiome – diet, inflammation, antibiotics – also influence the vaginal microbiome. There’s no proven direct line from AS to a disrupted vaginal microbiome, so treat this as a plausible connection rather than a settled one. That said, if you’re on repeated courses of antibiotics for AS-related infections, keep an eye on your vaginal health, since broad-spectrum antibiotics can knock back protective Lactobacillus and open the door to thrush or bacterial vaginosis.

Treatments for AS

Drugs

The standard medical model for treating AS uses painkillers, glucocorticoids and immunosuppressive drugs. These are usually not fully effective at preventing the disease from progressing, though they can provide symptom relief. Long-term use is associated with bone and muscle wasting and cardiovascular problems.

Diet

Diet establishes and maintains the gut microbiome, with different nutrients shaping the microbial communities and providing substrates for microbial metabolism. Indigestible carbohydrates are fermented by gut microbes into short-chain fatty acids, which help regulate immune function⁶ and intestinal hormone production. The gut is the largest endocrine (hormone) and immune organ in the body, so working on the digestive tract in autoimmune disease is a sensible first step.

Changing the diet to shift the gut microbiome and reduce intestinal inflammation could help. One study reported that people on a high-carb/low-protein diet had around 40 times more K. pneumoniae than those on a low-carb/high-protein diet⁸. A low-starch diet may therefore reduce inflammatory activity and slow disease progression in AS, and potentially in other reactive arthritis conditions.

A low-carb/high-protein diet can be used alongside drugs, with or without antimicrobial therapy, which might take the form of targeted herbal medicine or antibiotics.

Plenty of dietary approaches are known to help with autoimmune disorders, such as the autoimmune protocol (AIP), gluten-free, dairy-free, paleo, low-FODMAP and others. The exact mechanism behind these changes isn’t fully understood, but it’s thought to come from cutting irritants, allergens and ‘unfriendlies’ out of the digestion to reduce immune responses and inflammation. If you’ve been diagnosed with AS, diet is a great place to start.

Herbal antibiotics

There are many alternatives to pharmaceutical antibiotics. Please see an experienced naturopath or herbalist for comprehensive treatment.

Frequently asked questions

Can ankylosing spondylitis cause painful sex?

Yes, it commonly does, though usually indirectly. AS affects the sacroiliac joints, hips and spine, so stiffness, pain and reduced mobility can make certain positions uncomfortable or off-limits. Fatigue and the low mood that often accompanies chronic pain also dampen desire and arousal. In one study, women with AS scored lower across all measures of sexual function than women without it³.

If sex hurts, it’s worth pulling apart the cause. Joint pain and positioning are one thing; pain at the vaginal opening or deep pain that persists regardless of position may point to a pelvic floor or gynaecological issue that deserves its own assessment. A pelvic health physiotherapist and your rheumatologist working together can make a real difference.

Is there a link between UTIs and ankylosing spondylitis?

There does seem to be. Genitourinary infections show up more often in women with AS than in women without it², and in HLA-B27-positive people an infection may act as a trigger that sets AS in motion. Certain gut bacteria linked with AS, such as Klebsiella, are also common causes of urinary tract infections.

This doesn’t mean every UTI leads to AS – most don’t, and most people with recurrent UTIs never develop it. But if you have AS and keep getting urinary or vaginal infections, treat them as connected rather than random, and tell your doctor about both so they can look at the bigger picture.

Will changing my diet help my AS?

It might, and it’s low-risk to try. The thinking is that reducing starch and refined carbohydrates lowers the fuel available to gut bacteria such as Klebsiella, which may in turn reduce the immune reaction thought to drive AS. One study reported around 40 times higher K. pneumoniae counts on a high-carb/low-protein diet compared with a low-carb/high-protein one⁸.

The evidence isn’t strong enough to promise results, and diet is not a replacement for the treatment your rheumatologist prescribes. But approaches like the autoimmune protocol, gluten-free or low-starch eating are worth a supervised trial, ideally with a practitioner who can help you keep it nutritionally complete and track whether your symptoms actually improve.

This article is for general information and is not a substitute for individual medical advice. Ankylosing spondylitis is a serious condition that needs proper diagnosis and monitoring. Always talk to your doctor, rheumatologist or a qualified practitioner before changing your treatment, starting a new diet or taking herbal medicines, particularly if you are pregnant, breastfeeding or on other medications.