Changes of serum anti-thyroid antibodies during and after pregnancy in autoimmune thyroid diseases.

Changes of serum anti-thyroglobulin haemagglutination antibodies (TGHA) and anti-thyroid microsomal haemagglutination antibodies (MCHA) were observed during pregnancy and after delivery in Graves' disease and autoimmune thyroiditis. Both TGHA and MCHA decreased as pregnancy progressed, and sometimes they became negative in late pregnancy. Transient increases of TGHA and MCHA were observed after delivery and the antibody titres reached peaks about 3-4 months post-partum in more than halft the patients. In some patients, antibodies developed after delivery. Similar transient increases of antibodies were observed after spontaneous and therapeutic abortion. These changes seem to be induced by physiological and immunological changes occurring during pregnancy and after delivery.