Endocrine Abstracts

Pregnant women may require treatment of hypo- or hyperthyroidism, L-thyroxine (LT4), propylthiouralcil (PTU) and methimazole (MMI) being the most frequently used drugs. Aim of this study was to verify the consequences on both the mother and the fetus of pharmacological treatment during pregnancy. We retrospectively evaluated 292 pregnancies: 63 patients under MMI treatment, 8 of whom (7 Graves’ (GD) and 1 toxic nodular goiter) still hyperthyroid in spite of treatment (H-MMI) and 55 euthyroid (E-MMI); 26 GD patients under PTU, 6 of whom still hyperthyroid (H-PTU) and 20 euthyroid (E-PTU); 139 women under LT4 therapy, suppressive (SUP) for nodular goiter or replacement (REP) for hypothyroidism. These two last groups were further subdivided in adequate REP or SUP or non-adequate REP or SUP on the basis of TSH serum levels. We also included 64 untreated (EU) patients with thyroid disease: 41 Graves’ euthyroid after MMI, PTU or 131-I treatment, 16 multinodular goiter and 7 chronic autoimmune thyroiditis. The prevalence of miscarriages and fetal abnormalities, newborns’ weight and length and neonatal TSH values were evaluated. Results were analyzed by Student t-test. Miscarriage occurred in: 7/55 (12.7%) E-MMI, 2/8 (25%) H-MMI, 3/20 (15%) E-PTU, 3/74 (4.1%) adequate REP, 1/17 (5.9%) non-adequate REP, 1/21 (4.8%) adequate SUP and 6/64 (9.4%) EU. 1 E-PTU and 2 EU underwent voluntary miscarriage for a prenatal diagnosis of Down (2) or Klinefelter (1). Neonatal TSH values, weight and length at time of birth did not present significant differences between all the groups and normal pregnancies. All except 9 newborns (4 from adequate REP, 2 from EU, 2 from E-MMI mothers and 1 from E-PTU) were born at term. In 1 H-PTU a fetal goiter occurred, in 1 adequate-SUP a genital malformation and in 1 EU a renal malformation occurred. In summary, neonatal TSH values, weight and length were not different between groups and the prevalence of miscarriages and fetal malformations was not higher than that reported in the literature. These results indicate the safety of LT4, MMI and PTU treatment during pregnancy.