Fetal pituitary responds to thyroid-releasing hormone (TRH) from the hypothalamus.
Duration: 15 weeks
Howdeshell KL. 2002. A model of the development of the brain as a construct of the thyroid system. Environ Health Perspect 110 (suppl 3):337-348.
Fetal cortex grows in size; cortical cells attain maximal size late in gestation. There is a marked increase in fetal adrenal 3beta-HSD activity, which indicates an increase in serum concentrations of cortisol.
Duration: 13 weeks
Pepe GJ, Albrect ED. 1990. Regulation of the primate fetal adrenal cortex. Endcrine Reviews 11(1):151-176.