Table 3.

Mean serum hormone concentrations (SD) by visit during gestation (N = 106 pregnant women)

Biomarker	Visit 1 (14–20 weeks)	Visit 3 (24–28 weeks)	p-value*
Thyroid Hormones
TSH (uIU/mL)†	1.10 (1.60)	1.17 (1.65)	0.25
Free T3 (pg/mL)	4.01 (0.61)	3.86 (0.59)	0.02
Free T4 (ng/dL)	1.45 (0.31)	1.32 (0.32)	0.001
Sex Hormones
Progesterone (ng/mL)†	46.9 (1.37)	88.4 (1.48)	<0.001
Estradiol (ng/mL)	5.70 (2.48)	11.1 (3.60)	<0.001
SHBG (nmol/L)	349 (108)	391 (106)	0.002

SD, standard deviation, TSH, thyroid-stimulating hormone, SHBG, sex hormone-binding globulin.

†Geometric mean and geometric standard deviation reported.

*Test for fixed effects from linear mixed models with random intercepts.