Safety of pharmacological treatment of thyroid diseases &br;during pregnancy
Elena Gianetti, Massimo Tonacchera, Laura Russo, Paolo Vitti & Aldo Pinchera
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 of pharmacological treatment during pregnancy. We retrospectively evaluated 379 pregnancies: 124 patients under MMI treatment, 35 of whom still hyperthyroid in spite of treatment (H-MMI) and 89 euthyroid (E-MMI); 52 GD patients under PTU, 20 of whom still hyperthyroid (H-PTU) and 32 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 nodular goiter or autoimmune thyroid disease. 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: 9/89 (10.1%) E-MMI, 3/35 (8.5%) H-MMI, 4/32 (12.5%) 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. In 2 H-PTU newborns a fetal goiter and a hypertrophic pyloric stenosis 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 that currently there are not contraindications for the use of LT4, MMI and PTU treatment during pregnancy.