Clinical and laboratory findigns of gestational thyrotoxicosis, determination of free T4 reference intervals for the pregnancy variety effect antithyroid drug start

There are many reasons for hyperthyroidism in pregnancy and Gestational Transient Thyrotoxicosis is a non-autoimmune thyrotoxicosis caused by an increase in hCG level in the first trimester of pregnancy. The hCG level falls in the later stages of pregnancy and this condition usually improves and treatment is not required. However, during pregnancy the symptomatic and spontaneous remission of the medication may be necessary. In this study, we aimed to invastigate clinical findings, laboratory parameters, course of free T4 level during pregnancy, initiation of drug administration, pregnancy complications and which free T4 levels should be accepted in order to initiate the drug in pregnant women who have applied to our clinic and thyrotoxicosis. Forty-five female patients who were admitted to GOP University Medical Faculty Endocrinology and Metabolism Policlinic and who were diagnosed with gestational thyrotoxicosis were included in the study. Free T4, TSH, anti TPO levels, hemogram, biochemical parameters of patients were studied. Patient's thyroid hormone levels and gestational symptoms were monitored at frequent intervals. Only 15 of these patients (33%) were on medication and 30 patients (66.7%) were followed without medication. The free T4 levels of the patients who started the medication were found to be 2,89 ± 0,99 ng/dL. 10 patients had severe nausea vomiting, palpitation in 3 patients and no sypmtoms in 2 patients. Patients started to take medication 10,7 ± 4,2 weeks on average and the mean duration of medication was 10,13 ± 6,52 weeks. In all patients, the drug was discontunied on the grounds that the free T4 level returned to normal and complaints improved. In the present study we found that the initial free T4 level of the 15 patients who were diagnosed with gestational transient thyrotoxicosis and who strated the drug was 2,89 ± 0,99 ng/dL. The patients used medication for a mean of 10,13 ± 6,52 weeks and there was no medication until the end of the pregnancy. There is a need for extensive prospective studies to examine more patients to determine which free T4 value to initiate the drug. Key words: Gestational, thyrotoxicosis, free T4, antityhroid drug