Effects of Pregnancy and Delivery Methods on Change in Ankylosing Spondylitis Treatment Using the Korean Health Insurance Review and Assessment Service Claims Database

BACKGROUND: Women with ankylosing spondylitis (AS) show a higher rate of cesarean section (CS) compared with healthy women. In this study, we determined the effects of pregnancy and delivery methods on AS worsening by analyzing prescription patterns. METHODS: The subjects were women with AS aged 20–49 years listed in the Korean Health Insurance Review and Assessment Service claims database. Change in treatment was defined as change in prescriptions 1–2 years before delivery or 1 year after delivery. We compared change in prescriptions between AS women with delivery or without delivery (1:1 matched). Moreover, we evaluated change in prescriptions according to delivery method among AS women with delivery. RESULTS: A total of 6,821 women with AS were included. Women in the delivery group (n = 996) were younger and showed less drug use and lower comorbidity rates than those in the no delivery group. Change in prescriptions did not differ between the delivery and no delivery groups (odds ratio [OR], 0.76; 95% confidence interval [CI], 0.56–1.05). Furthermore, the overall change in prescriptions did not significantly differ between vaginal delivery (VD) and CS (OR, 0.72; 95% CI, 0.45–1.14). CONCLUSION: The rate of change in prescriptions was comparable between AS patients with and without delivery. There was no association between the method of delivery and change in prescription. Therefore, pregnancy and VD may not be the factors associated with AS worsening.