FIGURE 1 Serum total T4 and free T4 levels by trimester
From the following article:
Therapy Insight: management of Graves' disease during pregnancy
Grace W Chan and Susan J Mandel
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Figure 1. Serum total T4 and free T4 levels by trimester
The shaded boxes show interquartile ranges, with the median value also indicated. Serum total T4 levels rise to approximately 1.5-times the normal NP reference range. Although serum free T4 ranges were method-dependent, as shown by the differences in measurement by the Elecsys® (Boehringer Mannheim GmbH, Mannheim, Germany) and Tosoh® (Tosoh Corporation, Yamaguchi, Japan) methods, both methods show a consistent decrease in free T4 levels as pregnancy progresses. Figure courtesy of Carole Spencer.13 Abbreviations: 1st, first trimester (n = 105); 2nd, second trimester (n = 39); 3rd, third trimester (n = 64); NP, nonpregnant (n = 62).
