To evaluate the influence of pregnancy on the morbid condition of Takayasu arteritis, we summarized the clinical data and pregnant courses of 18 patients with Takayasu arteritis and a total of 22 deliveries. We followed C-reactive protein (CRP) scores in 16 of 18 patients (20 of 22 deliveries) to ascertain the inflammatory condition inherent in Takayasu arteritis 1 year prior to, during, and 1 year after pregnancy. We also evaluated digital plethysmograms (pulse amplitude, pulse wave, crest time) to follow the hemodynamical condition of patients before, during, and after pregnancy. CRP scores improved significantly during pregnancy and 1 year after delivery. In the digital plethysmograms, pulse amplitude and wave also exhibited improvement after delivery, but crest time remained unchanged. This indicated that pregnancy is a state favorable to this disease. Some factors, such as the sex hormone progesterone, may induce this condition, but the details are still unknown. In conclusion, inflammatory activity and the hemodynamic state improve with pregnancy in patients with Takayasu arteritis. The physiologic aspects which cause this improvement should be maintained even after pregnancy.