THYROID ANTIBODIES DURING PREGNANCY AND IN THE NEWBORN*

Abstract

Twenty-two women, found to have circulating antithyroid antibody (AAB) either before or during pregnancy, were observed during 23 pregnancies. The maternal AAB titers began to fall as early as the first trimester, tended to strike a plateau at a low level in the third trimester, and rose again during the first few months after the termination of pregnancy. These antibodies were demonstated in the cord blood of 8 newborn infants of 9 mothers who had demonstrable circulating AAB at the time of delivery, but could not be demonstrated in the cord blood of 7 newborn infants of mothers whose AAB titers had fallen to zero by the time of delivery. AAB disappeared from the blood of all infants during the first 3 months of life. No clinical evidence of hypothyroidism was found in the living offspring at birth or at the time of follow-up examination for as long as 2 years after birth. The levels of serum protein-bound iodine at birth in 6 newborn infants with proved transplacental transfer of AAB, and later in 4 of these subjects and 2 other offspring, were within the normal range for the ages concerned. It is concluded that the presence of AAB in the maternal and fetal circulations is not a cause of cretinism.