The influence of pregnancy on the course of ankylosing spondylitis (AS) was evaluated for 87 pregnancies of 50 patients. Remission of AS was recorded in 18 pregnancies, exacerbation in 21, and no change in 48. A short flareup of AS was noticed postpartum in 45% of the patients. Postpartum anterior uveitis occurred frequently (20%). The first symptoms of AS were often (20%) related to pregnancy. AS had no harmful effect on pregnancy, the fetus, or the newborn. Twelve percent of the offspring who were 18 years old or older have developed definite ankylosing spondylitis.