Transient Non-Autoimmune Hyperthyroidism of Early Pregnancy

Figure 1

A representative example of transient hyperthyroidism of hyperemesis gravidarum. By week 6, vomiting begins and becomes severe by week 10. Serum-free thyroxine (T4) index is elevated and thyrotropin is suppressed. By weeks 16 to 18, vomiting subsides with marked improvement of the free T4 index value. During this period, the patient loses 3.6 kg. By week 18, the serum free T4 index returns to normal, but the serum thyrotropin remains suppressed until week 26. Patient regains and gains weight with a term delivery of a healthy infant. The gray band indicates reference range. LNMP: last normal menstrual period. Patil-Sisodia and Mestman [12].