Endocrine Abstracts

Screening is a process of identifying apparently healthy people at increased risk of a disease or condition. They can then be offered appropriate treatment to reduce the risk arising from the disease or condition.

Thyroid autoimmunity (TAI), defined by the presence of antibodies against thyroperoxidase and thyroglobulin, have been associated with adverse pregnancy outcomes, infertility, and impaired child neurodevelopment. However, associations do not necessarily mean a causal relationship. Other risk factors associated with TAI should be considered, including other organ specific autoimmunity, age, smoking and BMI. Moreover, thyroid autoimmunity can merely reflect an immune dysfunction. TAI is often related to the development of subclinical hypothyroidism during pregnancy, with an inadequate thyroid response to human chorionic gonadotropin. So far, the use of levothyroxine in interventional studies has not provided sufficient evidence to recommend its use in euthyroid TAI pregnant women. It remains unclear whether potential benefits outweigh the possible harm, due to overtreatment during pregnancy. Thyroid hormones (TSH, fT4) are important to sustain pregnancy and neonatal outcome. Clinical thyroid dysfunction (hypothyroidism, hyperthyroidism) should be diagnosed and treated. Subclinical hyperthyroidism has not been associated with adverse pregnancy outcomes. However uncertainty persists with regard to subclinical hypothyroidism. As for TAI, subclinical hypothyroidism has been associated with impaired child neurodevelopment and adverse obstetric outcomes. Intervention studies with levothyroxine in pregnant patients with subclinical hypothyroidism were unable to sustain an improvement in offspring’s neuropsychological development. The evidence for intervention with a reduction in adverse obstetric outcomes in this population is weak, with studies lacking adequate power and appropriate design. Also policy on cut-off levels to define TAI and suitable thyroid hormones in pregnancy remains to be determined. Therefore, we recommend against universal screening for TAI and thyroid hormones in pregnant women, but do acknowledge the use of a case finding approach.