Establishment of assay method‐ and trimester‐specific reference intervals for thyroid hormones during pregnancy in Chengdu, China

Background The reference intervals of thyroid hormone will change at different stages pregnancy because physiological alterations. On the other hand, also in detection systems due to manufacturer's methodology as well a race. objective this study was establish assay method- and trimester-specific for thyroid-stimulating hormone, free thyroxine triiodothyronine pregnant women Chengdu. Methods A prospective, population-based cohort involved 23,701 samples during three trimesters 8646 non-pregnant with pre-pregnancy clinical laboratory tests. 2.5th 97.5th percentiles were calculated each trimester according ATA Guidelines. Results interval has significant increasing trend from first trimester, second third which 0.08–3.79 mIU/L 0.12–3.95 0.38–4.18 respectively (p < 0.001). However, have decreasing trends 11.87–18.83 pmol/L 3.77–5.50 11.22–18.19 3.60–5.41 10.19–17.42 3.37–4.79 (both p Conclusion It is necessary thyroxine, these hormones are significantly pregnancy.