CRP and ankylosing spondylitis: There was a significant difference between the control group and the psoriatic arthritis, and the ankylosing spondylitis groups at preconception, and the 1st,2nd and 3rd trimesters regarding CRP and IL-17A (Fig. 2) while there was no statistically significant difference between preconception, and the 1st,2nd and 3rd trimesters with regard to CRP and IL-17A (Table 4).