Optimal cortisol concentration at the feto-maternal interface is crucial for early gestation.
Cortisol regeneration by 11β-HSD1 was mainly on the maternal side.
Cortisol inactivation by 11β-HSD2 was confined to the lining surfaces of both sides.
Cortisol upregulated 11β-HSD1 and 2 on the maternal and fetal sides respectively.