Fig. 5

Comparison between ATA and subgroup-specific reference intervals. A T1_a subgroup; B T1_b subgroup; C T2_a subgroup; D T2_b subgroup; E T3_a subgroup; F T3_b subgroup. The figure illustrates the gaps between estimated and fixed cut-off values. For all graphs, the solid red lines are the upper and lower reference limits suggested by the 2011 ATA. The dotted black lines are the upper and the lower reference limits derived from 1777 healthy pregnant women in our laboratory for each subgroup. For the subgroups T1_a and T1_b, the solid blue line corresponds to the upper reference limit proposed by the 2017 ATA (URL of 5.1 mIU/L, obtained by subtracting 0.5 mIU/L from the non-pregnant upper TSH level for T1_a and 4.0 mIU/L for T1_b subgroup)