Safety and Efficacy of Empiric Levothyroxine (LT4) Dose Increase Versus Individualized LT4 Dose Increase in Hypothyroid Women During Pregnancy
Safety and Efficacy of Empiric Levothyroxine (LT4) Dose Increase Versus Individualized LT4 Dose Increase in Hypothyroid Women During Pregnancy
In women who require thyroid hormone replacement medication, the investigators will compare 2
 ways to adjust thyroid medication during pregnancy to determine superiority in maintaining
 optimal blood levels of thyroid hormone. Thyroid hormone requirements increase significantly
 in pregnancy and it is important that blood levels of thyroid hormone remain normal so the
 fetus, which cannot make its own thyroid hormone has enough for early prenatal development.
 This trial compares 2 methods for adjusting thyroid medicine during pregnancy in women with
 known thyroid disease. Pregnant women (age 18 to 45) who take thyroid medication will be
 randomized to either 1) a 2-dose per week increase in thyroid medicine once pregnancy is
 confirmed, followed by dose adjustments every 2-4 weeks, or 2) adjustments in thyroid
 medication every 2-4 weeks in micrograms per day based on results of blood tests. The
 investigators will compare thyroid hormone levels throughout pregnancy between the groups of
 mothers to determine which method is superior in meeting the increased thyroid hormone
 requirements during pregnancy.
Inclusion Criteria:

 -  Female between ages of 18-45 who takes thyroid hormone replacement medicine AND
 pregnant or plan to become pregnant in the near future.

 Exclusion Criteria:

 -  Males

 -  Younger than 18 or older than 45 years old

 -  More than 10 weeks pregnant at enrollment

 -  Iodine deficient

 -  Pregnant with more than one baby (i.e., twins, triplets, etc.)

 -  NOT taking thyroid hormone medicine before becoming pregnant

 -  Levels of thyroid hormone in blood have been too low or too high in the past 6 months

 -  Treated with radioactive iodine in the past year.