Objective: To study reproductive performance and interaction between ankylosing spondylitis (AS) and pregnancy in a large population of female patients.
Methods: In collaboration with the Ankylosing Spondylitis International Federation, a questionnaire including clinical data and details on past and recent pregnancies was sent to the female members of national and regional AS societies in the USA, Canada, and 11 European countries.
Results: Nine hundred thirty-nine questionnaires were completed, showing the following clinical data. Mean age at onset of AS was 23 years. The onset was related to a pregnancy in 21%. The frequency of accompanying features of AS was as follows: peripheral arthritis 45%, acute anterior uveitis 48%, psoriasis 18%, and inflammatory bowel disease 16%. Six hundred forty-nine women with previous pregnancies had on average 2.4 pregnancies per woman, of which 1.4 pregnancies were during disease. Of pregnancies 15.1% ended with miscarriage. Disease activity during 616 previous and 366 recent pregnancies was unchanged in 33.2%, improved in 30.9%, and worsened in 32.5%. Improvement of disease activity during pregnancy was correlated with a history of peripheral arthritis. It was also observed more often among those having a female than a male child (p = 0.02). A postpartum flare within 6 months after delivery was experienced by 60%, most often patients with active disease at conception. Delivery occurred at term in 93.2% of cases. The rate of cesarean section was high and due to AS in 58% of cases. The majority of neonates were healthy and had a mean birthweight of 3339 g. AS had an adverse effect on being a mother and a caregiver.
Conclusion: AS did not adversely affect fertility, pregnancy outcome, or the neonate. Improvement during pregnancy was related to a history of peripheral arthritis and a female fetus. Active disease at conception was a predictor of a postpartum flare.