Ankylosing spondylitis (AS) causes inflammation in the joints of the spine, lower back, and pelvis. Females may also be more likely to have pain in the neck, knees, and ankles, as well as systemic symptoms, such as bowel inflammation.
A note about sex and gender
Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.
Historically, experts considered ankylosing spondylitis (AS) to be a health issue that mainly affected males. More recent research indicates that it is nearly as prevalent in females and that its severity has nothing to do with a person’s sex.
The belief that AS mainly affects males likely resulted from an underrepresentation of females in related research, according to a
The team behind the review also found that females with AS have a higher disease burden than males — due to longer delays in diagnosis, high levels of disease activity, and less responsiveness to treatments that target tumor necrosis factor (TNF).
TNF is a protein in the body linked with inflammatory conditions such as arthritis. A few examples of medications that act on TNF include etanercept (Enbrel) and adalimumab (Humira).
This article looks into the prevalence and symptoms of AS in females, as well as other aspects of the disease.
AS can affect anyone. As the Spondylitis Association of America points out, the disease and its severity have nothing to do with a person’s sex.
Symptoms of AS vary from person to person. Some common early symptoms include:
- frequent, dull pain and stiffness in the lower back and the joints connecting the spine and hips
- back pain that is worse in the mornings and at night but can be relieved with a warm shower or exercise
- pain that may be one-sided
- a low-grade fever
- a loss of appetite
- a general feeling of discomfort
The Spondylitis Association of America observes that the symptoms of AS can present differently in females, compared with males. For example, a female with AS may first have pain in the neck, or elsewhere, rather than the lower back.
As AS progresses, the symptoms may change and include:
- pain on both sides of the body
- stiffness and pain in the neck, ribs, shoulder blades, hips, and heels
- increased fatigue
- mild to moderate anemia
Do females have the pain in different places?
AS affects the same joints, regardless of sex. However, females may be more likely to experience pain in the neck, knees, and ankles.
Systemic symptoms related to AS, such as bowel inflammation, may also be more common in females, compared with males.
Experts still debate whether sex is a risk factor for AS.
The healthcare community is still unsure of the exact cause of AS, but genetics may be partially responsible. The Spondylitis Association of America notes that most people with AS have a gene that makes a protein called HLA-B27.
Having this gene does not guarantee that a person will develop AS, however, and some people without the gene still develop the disease.
This leads scientists to believe that other genetic factors and a triggering infection or injury causes people with a risk of AS to develop it.
Risk factors for AS include:
- the HLA-B27 marker gene
- an age of 17–45
- a family history of AS
- bowel inflammation
- changes in gut bacteria
- recurrent gastrointestinal infections
- inflammatory bowel disease
According to the Arthritis Foundation, having AS does not affect fertility or reproductive health. However, a person with AS who is planning to become pregnant should discuss family planning and care with a rheumatologist.
A rheumatologist and obstetrician can guide a person with AS toward pregnancy-safe treatments. Some treatments for AS, such as methotrexate or nonsteroidal anti-inflammatory drugs (NSAIDs), may be harmful during pregnancy.
AS symptoms may continue throughout a pregnancy, remaining stable or worsening. In some people, the symptoms may lessen.
AS may make vaginal delivery more difficult, due to inflammation in the hip joints. This means that someone with AS may be
Treatment for AS is very similar, regardless of sex. It can consist of:
- physical therapy
Doctors may prescribe multiple medications, including:
- NSAIDs to relieve pain and inflammation
- corticosteroids to reduce inflammation
- biologic drugs, such as TNF inhibitors, to treat arthritis in the joints and inflammation in the gut and eyes
While AS treatment is similar for everyone, females
Complications of AS can vary in severity and occurrence from person to person. They can develop in anyone with the disease.
AS complications can include:
- inflammation of the eyes, or uveitis
- the spinal vertebrae fusing, resulting in stiffness and inflexibility
- compression fractures
- reduced lung capacity, due to rib cage immobility
- cardiac system problems, such as inflammation of the root of the aorta
Additionally, certain side effects may occur more frequently in females than males, including:
- pain during the night
- trouble sleeping or staying asleep
- a reduced quality of life
Males with AS tend to receive the diagnosis earlier than females.
A large review showed that males with the condition got the diagnosis 2.3 years sooner than females. When the review adjusted for the quality of the reports reviewed, it found that males received the diagnosis 7 months sooner.
The belief among healthcare professionals that AS primarily affects males, combined with publication bias, may be responsible for the delay in diagnosis for females.
The same review found no differences in symptoms of AS that were significant enough to account for the discrepancy in diagnostic timing.
Imaging technology and the standards for diagnosis may also account for some of the delay. Diagnostic criteria for AS include damage to the spinal joints that is visible on X-rays. The Global Healthy Living Foundation reports that males are more likely to have damage that is visible in this way, compared with females.
Anyone who suspects that they may have AS should contact a doctor.
A person with AS should see a doctor regularly and let them know about any new or worsening symptoms.
Also, people who are considering becoming pregnant should consult a doctor first. They can recommend pregnancy-safe AS treatments.
AS is a form of arthritis that causes inflammation in the spinal joints. It can lead to chronic pain and mobility problems.
Doctors once believed that AS primarily affected males. However,
Due to underrepresentation in research and other factors, it takes longer for doctors to diagnose AS in females, compared with males. Also, symptoms may present differently in females, and certain AS medications may be