Objective To investigate the changes of serum vitamin E in pregnant women with autoimmune thyroid diseases and provide evidence for clinical prevention of adverse pregnancy caused by oxidative stress. Methods Randomly selecting 221 cases of obstetrics and gynecology pregnant women in outpatient clinics in Chancheng District Central Hospital. A double antibody one-step sandwich enzyme-linked immunosorbent assay (ELISA) was used to detect vitamin E concentration. Results The results of 221 subjects were normally distributed. The vitamin E concentration in the disease group was (353. 93 ± 141. 28) mmol/L, and the control group was (310. 49 ± 105. 49) mmol/L. There was a significant difference between the two groups (P＜0. 05). The concentration of vitamin E in different gestational weeks gradually decreased with the increase of pregnancy, and the difference between them was statistically significant (F = 8. 417, P＜0. 05). Conclusion The presence of oxidative stress during pregnancy in women with autoimmune thyroid diseases should be valued by clinicians.