Non invasive methods: maternal antithyroid antibodies and ultrasound measurement of the fetal thyroid gland could be an important tool for detecting fetal thyroid dysfunction in mothers with autoimmune thyroid disease.

Autoimmune thyroid disease complicates 5-20% unselected pregnancies. The crucial impacting factor on the pregnancy outcomes in mothers with autoimmune thyroid disease is the thyroxine level changes.

But, fetal hypo or hyperthyroidism can be found in treated pregnant women with autoimmune thyroid disease, even when their thyroid hormones are in normal range, because thyroid antibodies, antithyroid drugs and iodine pass the placenta.

Our previous results show that high fetal free thyroxine (fT4) levels measured by cordocentesis are unexpectedly frequent in women with autoimmune thyroid disease, including maternal autoimmune hypo- and hyperthyroidism. Increasing awareness that even some mild fetal disorder can have an impact on later neurophysiologic development and the health of an individual makes the recognition and therapy of fetal hypo- or hyperthyroidism an increasingly significant domain of interest. According to our results, fetal fT4 concentrations did not correlate neither with dose of medication nor with ultrasound biometric parameters; the range for maternal thyroid-stimulating hormone (TSH) correlated predominantly with normal fT4 can not be marked off. The type and concentration of antithyroid antibodies might have some prognostic value.

There is a growing list of publications referring to the ultrasound measurement of the fetal thyroid as an important tool for detecting fetal thyroid dysfunction. Fetal thyroid measurement became a part of the clinical guidelines for pregnancies complicated with maternal thyroid disease.

Inclusion Criteria:

• Pregnant women diagnosed and treated for autoimmune hyper or hypothyroidism: - Disease diagnosed by an endocrinologist, based on clinical and laboratory tests and ultrasound thyroid examination.
• All of the hyper or hypothyroid women have to be positive for one or both thyroid antibodies when entering the study.
• Patients with autoimmune thyroid disease will be included into the study in the first half of pregnancy, but not later than 20th weeks of gestation
• For the pregnant women in control group:
• if they are euthyroid, with antithyroid antibodies within reference range, healthy and have uncomplicated pregnancy

Exclusion Criteria:

• Patients with chronic diseases (except for thyroid disease) in their past medical history record. Pregnancy induced diseases are not a part of the exclusion criteria (gestational diabetes and pregnancy induced hypertension)
• all the patients whose pregnancies resulted from assisted reproductive technologies will be excluded from the study.
• mothers from the control group will be excluded, if the neonate have abnormal thyroid function

Groups are selected from State tertiary referral centre for Gynecology and Obstetrics