https://orcid.org/0000-0002-8029-7355 *These authors contributed equally to this work. Background/Aims: Because ankylosing spondylitis (AS) mainly affects sacroiliac joints, special attention should be given to normal labour and pregnancy outcomes. Here, we investigate pregnancy outcomes in Korean women with AS. Methods: Based on data from the Korean Health Insurance Review and Assessment Service claims database since July 2007, maternal complications were compared between women with AS and 1:10 matched general population by maternal age and year of delivery. Additionally, the 27 deliveries from 21 patients with AS who were seen at a tertiary hospital were retrospectively evaluated using 1:4 matched control group by maternal and gestational age. Results: In the population-based cohort, there were 1,293 deliveries in 996 patients with AS. Higher maternal age and more comorbidities were reported than in the general population. However, compared to age and delivery-year matched population, only the rate of Caesarean section (CS) was higher in women with AS (odds ratio, 1.52; 95% confidence interval, 1.36 to 1.70). Incidence of other maternal complications was comparable between women with AS and control subjects. In the hospital-based cohort, the CS rate was higher in women with AS (44.4% vs. 20.4%, p = 0.002). Causes of CS was not different in both groups, including previous uterine surgery. There were no significant differences in foetal outcomes, including growth restriction, foetal malformations and Apgar score. Conclusions: CS deliveries were performed more often in women with AS. However, other maternal complications and offspring complications were similar between women with AS and healthy control subjects.