Background To evaluate obstetrical and perinatal outcomes of pregnancies with ankylosing spondylitis (AS). Methods This was a retrospective study evaluating obstetric outcomes of 52 patients with AS who were followed up at our institution between 2006 and 2019. Patients were classified as having disease greater than or less than 5 years, and according to disease-related medical treatment during pregnancy, as drug free, single medication or multiple medication. Results Overall rates of preterm delivery, intrauterine growth retardation and preeclampsia were 17.3%, 13.4% and 7.7%, respectively. Thirty-three of the patients were followed up without any medication, while 19 patients used drugs during pregnancy. Seven patients used a single drug and 12 patients had multiple drugs. There was no significant difference in terms of obstetrical and neonatal outcomes. However, a higher rate of neonatal intensive care unit (NICU) admission was observed in the group using medication for AS, despite a lack of statistical significance (31.5% vs 15%, P = .162). On the other hand, patients having disease more than 5 years had higher rates of Apgar scores less than <7 and admission to the NICU despite a lack of statistical significance (4% vs 7.4% and 16% vs 26%; P = .267 and P = .297, respectively). Conclusion In conclusion, pregnancies of patients with AS must be considered as high risk due to increased rates of adverse outcomes such as preterm delivery, intrauterine growth retardation or preeclampsia.