Hyperthyroidism during pregnancy is uncommon and
has been reported as occurring in 0.05–3.0% of
pregnancies (1, 2). The clinical diagnosis of hyperthyroidism
may be difficult in pregnant women, as symptoms
and signs of nervousness, sweating, and dyspnea;
tachycardia and cardiac systolic murmur are seen in
most normal pregnancies. More specific findings such as
weight loss, goiter, and ophthalmopathy may suggest
Graves’ hyperthyroidism (3, 4). In addition, the occurrence
of transient hyperthyroidism of hyperemesis
gravidarum may complicate the diagnosis (5, 6). The
diagnosis of hyperthyroidism should always be confirmed
by the measurement of circulating free thyroxine (FT4)
and TSH. Serum T4 concentration (both total and free)
varies during normal pregnancy and normal range
values of total and FT4 and free tri-iodothyronine (T3)
as well as TSH concentrations must be developed for each
specific trimester of pregnancy (4, 7).