Maternal Hypothyroidism in Pregnancy
Condition: Hypothyroidism
MeSH terms: Hypothyroidism
Study type: Observational

Summary: 
      There is general agreement that thyroid gland function should be assessed in pregnant women.
      When the gland produces too little thyroid hormone (hypothyroidism), all of the woman's
      bodily functions slow down, and there are problems with her baby's development. Until now,
      physicians have identified this problem on an individual basis (case-finding), but this
      approach misses many of the cases. Our trial aims to replace case-finding with a routine
      blood test that is highly effective at detecting hypothyroidism, thereby allowing treatment
      to correct the deficiency. This approach can eventually be implemented throughout the United
      States.
    

Detailed description: 
      This is a model community-based trial in Rhode Island (RI), aimed at avoiding or minimizing
      morbidity from overt maternal hypothyroidism by systematic detection and treatment, beginning
      at the 1st prenatal visit. This model can be superimposed on existing prenatal screening
      programs and is intended ultimately to replace "case-finding", which has recently been shown
      ineffective. Three aspects of maternal and child health are compromised when a pregnant woman
      is thyroid deficient: 1) the woman's own health and well-being; 2) her baby's brain
      development; and 3) overall health of the pregnancy (e.g., fetal death, prematurity,
      preeclampsia). Thyroid stimulating hormone (TSH) measurement, a well accepted indicator of
      thyroid dysfunction, will serve as the primary test for both diagnosis and monitoring. A TSH
      value >10 mU/L indicates overt hypothyroidism. Among the state's 14,000 annual pregnancies,
      42 women (0.3%) will be overtly hypothyroid early in gestation (32 undiagnosed, and 10
      under-treated). TSH values between 4.5 mU/L (98th centile) and 9.9 mU/L indicate subclinical
      hypothyroidism. The 240 women in this category will also receive treatment, and information
      will be gathered about disease progression to inform future practice. Approximately half of
      all RI's pregnancies are cared for by practices in Greater Providence, and TSH testing will
      initially be introduced, there. The research component is also within that area. Testing will
      subsequently be extended to the entire state. The program is centrally managed by three units
      at Women and Infants Hospital, in consultation with RI's Birth Defects Program Director.
      Program goals are to: provide TSH testing to at least 70% of pregnant women in Greater
      Providence; provide TSH testing to at least 50% of pregnant women elsewhere in RI; test 70%
      of screened women by 12 weeks' gestation, and 90% by 18 weeks' gestation; begin treatment in
      Greater Providence by 13 weeks' in 70%, and by 19 weeks' in 90%; document successful
      treatment during pregnancy in 90% (TSH >0.1 mU/L and <2.0 mU/L; retain 95% treated women to
      end of pregnancy, and 90% for up to 1 year postpartum; obtain pregnancy complications and
      birth outcomes for the entire cohort (Vital Records).

      Data will be collected on participation by practices and women, % of women with undiagnosed
      thyroid deficiency, compliance with follow-up and treatment during pregnancy and for up to
      one year afterwards, outcomes of their pregnancies, % of hypothyroid women with postpartum
      thyroid dysfunction, % of women with subclinical hypothyroidism who remain hypothyroid one
      year postpartum, physician attitudes, and program costs.
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The subjects will be 176 pregnant women and adolescents discovered to have varying degrees
        of hypothyroidism during the first and early second trimesters. This disorder will be
        identified by a blood test offered as part of routine prenatal care in a CDC-sponsored
        community-based program at prenatal practices in Providence, Rhode Island. These 176 women
        all will receive appropriate treatment for their hypothyroidism, and permission will be
        sought to record information about the natural history of their condition during the first
        postpartum year, as a way to inform future practice. The women will range in age from about
        17 to 44 years. Their racial/ethnic composition will reflect that of the general population
        of Rhode Island.
      
Biospecimen description: 
      Serum and urine samples from women who consent are to be stored in the freezer. Iodine
      measurements will be performed in urine samples and, possibly, serum samples. Consent is also
      asked for use of stored samples for other research purposes in the future.
    
Keywords: thyroid deficiency; pregnancy; post-partum thyroid dysfunction; permanent hypothyroidism