Progress of embryo in hours or days post ovulation
    Window of receptivity
Endometrium - edematous, secretory
  Decidual reaction
Glycogen, cytokine (LIF), integrin (avb3), pinopodes

Endometrium
Langman’s Medical Embryology, 8th ed., TW Sadler Lippincott, Williams & Wilkins (Philadelphia) 2000, p. 45 (revised)
Preceded and followed by refractory periods
P and E from CL
Receptive: progesterone (secretory) P receptor -> Stromal and glandular cells make cytokines (LIF, low levels of LIF associated with infertility)  pinopods, mucus and growth factors  (HB-EGF expressed by endometrium and trophoblast) low HG-EGF associated with pre-eclampsia
hCG from embryo , Maternal recognition of pregnancy
Anti-hCG vaccines to control fertility (WHO trials)