NCT00388297

Thyroid Therapy for Mild Thyroid Deficiency in Pregnancy

A Randomized Trial of Thyroxine Therapy for Subclinical Hypothyroidism or Hypothyroxinemia Diagnosed During Pregnancy

• Status: Completed
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 1,203 (actual)
• Sponsor: The George Washington University Biostatistics Center · Academic / Other
• Sex: Female
• Age: —
• Healthy volunteers: Accepted

Summary

The purpose of this study is to determine whether treating women, who are diagnosed with a mild imbalance of thyroid hormones during pregnancy, with thyroid hormone replacement affects their children's intellectual development at 5 years of age.

Detailed description

Published research reports have stimulated national and international controversy regarding the value of maternal thyroxine therapy given to improve neurodevelopment of the fetus in women with variously defined hypothyroidism. These reports have led to conflicting and confusing recommendations as to whether or not all pregnant women in the U.S. should be screened for subclinical hypothyroidism or hypothyroxinemia. Pregnant women less than 20 weeks gestation will have a blood test to screen for subclinical hypothyroidism or hypothyroxinemia. If eligible for the trial, patients will receive levothyroxine or placebo until delivery. Blood draws will be done at monthly study visits and the dosage will be adjusted based on test results. The children of these patients will have developmental testing done annually until they are 5 years of age. Comparison(s): thyroxine supplementation versus placebo given during pregnancy to determine whether therapy is effective in improving intellectual ability at 5 years of age.

Conditions

• Subclinical Hypothyroidism
• Hypothyroxinemia
• Pregnancy

Interventions

Type	Name	Description
DRUG	Levothyroxine	Coded study drug is thyroxine encapsulated in a gel capsule; matching placebo contains only cellulose. Color of capsule corresponds to mcg dose level (100mcg or 25 mcg). Subjects in subclinical hypothyroidism stratum are started on 1 capsule of 100 mcg per day; subjects in hypothyroxinemia stratum are started on 2 capsules of 25 mcg per day. Thyroxine dosing adjustments for both strata are determined centrally, using an algorithm, based on results of monthly TSH or free-T4 assays. Subjects take study medication until delivery.
DRUG	Placebo for Levothyroxine

Timeline

• Start date: 2006-10-01
• Primary completion: 2015-08-01
• Completion: 2015-10-01
• First posted: 2006-10-16
• Last updated: 2019-02-21
• Results posted: 2019-01-30

Locations

14 sites across 1 country: United States