This sheet talks about having ankylosing spondylitis during a pregnancy or while breastfeeding. This information should not take the place of medical care and advice from your healthcare provider.

What is ankylosing spondylitis?        

Ankylosing spondylitis (AS) is a kind of arthritis that mostly affects the spine. Arthritis is a general term for inflammation or swelling of the joints in the body. Symptoms of AS can include swelling, stiffness and pain. Sometimes, advanced AS can lead to new bone formation that causes the spine to become stuck in one position or become fused. Symptoms of AS usually start in young adults.

Will having ankylosing spondylitis make it harder for me to get pregnant?

Women with AS typically have a similar chance of getting pregnant as compared to women without this condition.

How will pregnancy affect my symptoms?

Healthcare providers are not able to predict how symptoms might change, if at all, during pregnancy. Some studies suggest that symptoms stay about the same during pregnancy, while some women report an increase in certain symptoms, especially as the pregnancy gets further along. Other women’s symptoms improve during pregnancy. Pregnancy does not appear to protect against AS flare-ups like it might for other autoimmune conditions. A flare-up of symptoms is common in the first few months after delivery, but this does not mean that the severity of the symptoms will be long-term.

Does having ankylosing spondylitis increase my chance for a miscarriage?

At this time it is unknown as there are no published studies looking at AS and miscarriage.

Can having ankylosing spondylitis increase the chance for my baby to have a birth defect?

In every pregnancy, a woman starts out with a 3-5% chance of having a baby with a birth defect. This is called her background risk. There have not been any published studies to date looking at whether having AS by itself increasing the changes of birth defect in a baby. Many people with AS use medication. We recommend discussing your treatment options with your healthcare provider. Your healthcare provider can work with you to manage your medical condition during a pregnancy.

Does having ankylosing spondylitis mean I have a higher chance for a pregnancy complication?

 Several studies have not found an increased chance for pregnancy complications in women with AS. One study suggested that AS did increase the chance for delivery before 37 weeks (prematurity), low birth weight and/or the need for cesarean delivery. The risk for pregnancy complications may be linked with the severity of AS and/or whether a woman has additional medical conditions or develops preeclampsia (very high blood pressure and kidney / liver problems during pregnancy). It is possible for a woman with AS to have a vaginal delivery.

I am taking medication for ankylosing spondylitis. Can I take my medication during pregnancy?

Some medications used to treat AS are known to cause birth defects, but others have not been associated with a concern. For information on specific therapies see our medication fact sheets at or speak with a MotherToBaby specialist. It is also important that you discuss treatment options with your healthcare providers when planning a pregnancy, or as soon as you learn that you are pregnant.

Can I breastfeed if I have AS?

AS does not appear to affect a woman’s ability to breastfeed.

Can I take my medicines for ankylosing spondylitis while breastfeeding?

Many medications for ankylosing spondylitis can be used while breastfeeding. However, while some medications are low risk, others may be more concerning. For information on specific medications see our fact sheets or contact MotherToBaby. Be sure to talk to your healthcare provider about all your questions on breastfeeding.

What if the father of the baby has ankylosing spondylitis?

Some of the medications used to treat AS could have an effect on sperm production in men. This could make it harder to get pregnant. In general, exposures that fathers have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet on Paternal Exposures and Pregnancy at

MotherToBaby is currently conducting a study looking at ankylosing spondylitis and the medications used to treat AS in pregnancy. If you are interested in taking part in this study, please call 1-877-311-8972 or sign up at

Selected References:

  • Giovannopoulou E, et al. 2017. Ankylosing Spondylitis and Pregnancy: A Literature Review. Curr Rheumatol Rev. 13(3):162-169.
  • Jakobsson GL, et al. 2016. Pregnancy outcomes in patients with ankylosing spondylitis: a nationwide register study. Ann Rheum Dis.75(10):1838-42.
  • Lui NL, et al. 2011. Effect of pregnancy on ankylosing spondylitis: a case-control study. J Rheumatol 38(11):2442-4.
  • Ostensen M. The effect of pregnancy on ankylosing spondylitis, psoriatic arthritis, and juvenile rheumatoid arthritis. Am J Reprod Immunol. 28(3-4):235-7.
  • Ostensen M &Husby G. 1989. Ankylosing spondylitis and pregnancy. Rheum Dis Clin North Am. 15(2):241-54.
  • Ostensen M & Ostensen H. 1998. Ankylosing spondylitis–the female aspect. J Rheumatol.25(1):120-4.
  • Ostensen M, et al. 2004. A prospective study of pregnant patients with rheumatoid arthritis and ankylosing spondylitis using validated clinical instruments. Ann Rheum Dis. 63(10):1212-7.
  • Timur H, et al. 2016. Pregnancy outcome in patients with ankylosing spondylitis. J Matern Fetal Neonatal Med. 29(15):2470-4.
  • Tiseo BC, et al. 2016. Male fertility potential alteration in rheumatic diseases: a systematic review. Int Braz J Urol. 42(1):11-21.