Pregnancy and the incidence , diagnosing and therapy of 3 Graves ’ disease

21 Thyroid hormones are essential developmental factors, and Graves’ disease (GD) may 22 severely complicate a pregnancy. This review describes how pregnancy changes the risk of 23 developing GD, how early pregnancy by several mechanisms leads to considerable changes in the 24 results of the thyroid function tests used to diagnose hyperthyroidism, and how these changes may 25 complicate the diagnosing of GD. 26 Standard therapy of GD in pregnancy is antithyroid drugs. However, new studies have shown 27 considerable risk of birth defects if these drugs are used in specific weeks of early pregnancy, and 28 this should be taken into consideration when planning therapy and control of women who may in 29 the future become pregnant. 30 Early pregnancy is a period of major focus in GD, where pregnancy should be diagnosed as 31 soon as possible, and where important and instant change in therapy may be warranted. Such 32 change may be immediate stop of antithyroid drug therapy in patients with a low risk of rapid 33 relapse of hyperthyroidism, or it may be an immediate shift from methimazole/carbimazole (with 34 risk of severe birth defects) to propylthiouracil (with less risk), or maybe to other types of therapy 35 where no risk of birth defects have been observed. 36 In the second half of pregnancy, an important concern is that not only the mother with GD, 37 but also her foetus should have normal thyroid function. 38 Page 2 of 31