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Amerlex free triiodothyronine and free thyroxine levels in normal pregnancy
Author(s) -
PARKER JOHN H.
Publication year - 1985
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.1985.tb04868.x
Subject(s) - free thyroxine , pregnancy , triiodothyronine , reference range , endocrinology , medicine , second trimester , thyroid hormones , hormone , chemistry , gestation , zoology , biology , thyroid function , genetics
Summary. Free triiodothyronine (FT 3 ) and free thyroxine (FT 4 ) were measured in 159 women during normal pregnancy and compared with non‐pregnancy reference ranges for these hormones. FT 3 values fell from the reference level of 6·34 (SD 1·06) pmol/l to 3·87 (SD 0·54) pmol/l in the 3rd trimester; corresponding figures for FT 4 were: reference 16·92 (SD 2·97) pmol/l, 3rd trimester 11·29 (SD 2·01) pmol/l. There were no significant changes in the 1st trimester; 4% and 69% of FT 3 results in the 2nd and 3rd trimesters respectively fell below the reference range of mean ±2 SD. The corresponding findings for FT 4 were 4% and 42%. FT 3 correlated reasonably well with total T 3 ( r =0·90) and was acceptably precise (within‐batch CV 2·1% at 5·6 pmol/l, between‐batch CV between 3·1% and 4·7% at six levels).