Table 2. The comparison of endometrial and myometrial P₄ release.

		M	M	M
		Days 10 to 11	Days 12 to 13	Days 15 to 16
Pregnancy	E	E > M	-	-
	Days 10 to 11
	E	-	E = M	-
	Days 12 to 13
	E	-	-	E > M
	Days 15 to 16
Estrous cycle	E	E = M	-	-
	Days 10 to 11
	E	-	E < M	-
	Days 12 to 13
	E	-	-	E < M
	Days 15 to 16

E – endometrial P₄ release, M – myometrial P₄ release.