Thyroid function 101: In Pregnancy:
- 2,314 participants of the Swedish Environmental Longitudinal, Mother and child, Asthma and allergy study.
- Population-based prospective pregnancy cohort of mother–child pairs.
- The effect of thyroid antibodies on thyroid function.
- TPO antibody was excluded before determining the reference range for TSH, FT4, FT3, TT4 and TT3.
- TSH was 0.11-3.48 mU/L.
- Smoking exposure caused lower TSH.
Thyroid function during early pregnancy: The SELMA study
Exposure to tobacco smoke, as assessed by questionnaires and serum cotinine, was associated with lower TSH and higher FT3 and TT3. BMI and gestational age were the main determinants of TSH (only for BMI), FT4, FT3, TT4 and TT3.