10
Maternal Disorders
Thyrotoxicosis in Pregnancy
Î When a suppressed serum TSH is detected in the first trimester
(TSH less than the reference range), a medical history, physical
examination, and measurement of maternal serum Free T4 or total T4
concentrations should be performed. Measurement of TSH receptor
antibodies (TRAb), and maternal total T3, may prove helpful in
clarifying the etiology of thyrotoxicosis. (S-M)
Î Radionuclide scintigraphy or radioiodine uptake determination should
NOT be performed in pregnancy. (S-H)
Î The appropriate management of abnormal maternal thyroid
tests attributable to gestational transient thyrotoxicosis and/or
hyperemesis gravidarum includes supportive therapy, management of
dehydration, and hospitalization if needed. Antithyroid drugs are NOT
recommended, though beta-blockers may be considered. (S-M)
Î In all women of childbearing age who are thyrotoxic, the possibility of
future pregnancy should be discussed. Women with Graves' disease
seeking future pregnancy should be counseled regarding the complexity
of disease management during future gestation, including the
association of birth defects with antithyroid drug use. Preconception
counseling should review the risks and benefits of all treatment options,
and the patient's desired timeline to conception. (S-H)
Î Thyrotoxic women should be rendered stably euthyroid before
attempting pregnancy. Several treatment options exist, each of which
are associated with risks and benefits. These include
131
I ablation,
surgical thyroidectomy, or anti-thyroid drug (ATD) therapy. (S-M)
Î Women taking methimazole (MMI) or propylthiouracil (PTU) should
be instructed to confirm potential pregnancy as soon as possible. If
the pregnancy test is positive, pregnant women should contact their
caregiver immediately. (S-H)
