First- and Second-Trimester Reference Intervals for Thyroid Hormones during Pregnancy in “Rhea” Mother-Child Cohort, Crete, Greece

Table 4

Thyroid clinical entities in the general population of Rhea mother-child cohort based on: (i) the manufacturer’s and (ii) the derived reference limits.

Trimester	Reference limits	Normal thyroid function 𝑛 (%)^a	Subclinical hypothyroidism 𝑛 (%)^b	Clinical hypothyroidism 𝑛 (%)^c	Subclinical hyperthyroidism 𝑛 (%)^d	Clinical hyperthyroidism 𝑛 (%)^e
1st	Manufacturer	386 (84.3)	6 (1.3)	0 (0)	48 (10.5)	7 (1.5)
	Rhea cohort	371 (81.0)	31 (6.8)	0 (0)	1 (0.2)	10 (2.2)
2nd	Manufacturer	680 (86.6)	18 (2.3)	1 (0.1)	61 (7.7)	1 (0.1)
	Rhea Cohort	653 (82.2)	47 (5.9)	0 (0)	18 (2.3)	9 (1,1)

^aTSH between reference limits and free T4 between reference limits.
^bTSH over the upper limit of reference limits and free T4 between reference limits.
^cTSH over the upper limit of reference limits and free T4 under the lower limit of reference limits.
^dTSH under the lower limit of reference limits and free T4 between reference limits.
^eTSH under the lower limit of reference limits and free T4 over the upper limit of reference limits.