Fig. 1

The endometrium is exposed to hypoxic conditions in a temporal and spatial manner during endometrial breakdown and repair. A Time of progesterone withdrawal (0 h), hypoxia is detected in the decidualised cell mass (inset a), B 4 h after progesterone withdrawal (PWD), the decidualised cell mass is positively stained for pimonidazole. The luminal epithelium is unstained (inset b, arrows), C The intensity of staining is stronger at 8 h after PWD. A distinct gradient is detected at the border of basal layer and the decidualised functional layer (inset c), D At 24 h after PWD the re-epithelialisation luminal epithelium and the adjacent stroma is immunopositive (inset d). BL basal layer, DC decidualised cells, SC shed cells, asterisk evidence of hemosiderin, NPC negative primary control