After inclusion into the study, thyroid function tests (fT4, TSH), and auto-antibodies assessment (anti TPO, TRAK) were performed once every two months in mothers with AITD, and from the 24th week of gestation monthly. Treatment was adjusted accordingly. Ultrasound for fetal size, morphology and fetal heart rate (FHR) was performed once in two months, and from the 24th week of gestation, monthly. The fetal biophysical profile score was determined weekly from the 30th week of gestation. The single centre design was chosen: all fetal sonograms were performed by the same gynecologist. Cardiotocography was performed once weekly from the 30th week of gestation.