Hypothyroidism and Pregnancy — the Importance of TSH Management
A retrospective study followed 150 pregnancies in women with primary hypothyroidism. Levothyroxine was initiated before or during pregnancy, as soon as hypothryoidsim was detected. The objective was to relate pregnancy outcome to the severity of hypothyroidism and the management received, and to evaluate offspring health.
- Overt hypothyroidism: TSH>5 mlU/L, T4<4.5 μg/dL
- Subclinical hypothyroidism: TSH>5 mlU/L, T4>4.5 μg/dL
- Pregnant women were classified into 3 groups based on their thyroid function at the time of conception.
- The objective was to achieve TSH levels between 0.5-2.0 mIU/L. Adequate management was defined as TSH </ 4 mIU/L, and inadequate management as TSH >/ 4 mIU/L.
- The investigators concluded that the evolution of pregnancies did not depend on the severity of hypothyroidism, but on the TSH management received; suggesting a need for strict and frequent follow up.
According to the American Association of Clinical Endocrinologists guidelines, there are options
available for managing thyroid levels during pregnancy. TSH levels should be routinely checked
before pregnancy, and during the first trimester.8