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

Table 1

Demographic data for pregnant women in total and reference study population.

	Total study population^a			Reference population
	1st trimester	2nd trimester	3rd trimester	1st trimester	2nd trimester
Sample size (𝑛)	458	794	48	143	260
Age (years)^b	29.16 (5.12)	28.98 (5.19)	28.37 (4.61)	28.50 (5.09)	27.79 (4.95)
Greek origin 𝑛 (%)	369 (80.6)	698 (87.9)	42 (87.5)	114 (79.7)	221 (85)

^aWomen with available biological samples.
^bValues are expressed as mean (SD).