Organization of Teratology Information Specialists

Arthritis is a term that refers to inflammation (swelling, pain, and redness) in the joints. Ankylosing spondylitis (AS) is one type of arthritis that mainly affects the spine. This condition commonly causes back pain and stiffness that starts during the teenage years or early adulthood. Over time, AS can cause the spine bones to grow together, which limits the range of back movement. AS is a multifactorial condition, meaning that it is caused by both genetic and environmental factors. Genetic variations leading to changes in an immune factor called HLA B27 are associated with AS. However, most people who have the HLA B27 genetic risk factor do not develop AS. The other genetic and environmental factors contributing to AS are not known. 
 

Men are diagnosed with AS more frequently than women. However, because AS affects people at a young age, many women will have this condition during their child-bearing years. Although not well studied, it is generally felt that AS does not negatively affect fertility or pregnancy outcomes (Ostensen 1992, Gran and Ostensen 1998). Unfortunately, unlike some other arthritis conditions, pregnancy does not appear to significantly improve symptoms for individuals with AS (Forger et al. 2009), so medicine treatment will often still be required. Therefore, a medicine discussion with your doctors is especially important for women with AS who are planning a pregnancy or have learned they are pregnant.