Endometrial integrin expression in the early luteal phase in natural and stimulated cycles for in vitro fertilization

To investigate the effect of ovarian stimulation on integrin expression in the early luteal phase.Seven endometrial biopsies were taken 2 days after the oocyte retrieval from stimulated cycles for IVF and 23 from natural cycles, 2 days after ovulation.Endometrium was in-phase in 22/23 and 7/7 biopsies from the natural and stimulated cycles, respectively. Integrins alpha(1) and alpha(4) were simultaneously positive in 43.4% from the natural and in all (100%) the stimulated cycles (P0.03). On the day of the endometrial biopsy, progesterone serum values were higher in the stimulated cycles (55.2+/-9.5 microg/l versus 8.5+/-3.8 microg/l) (P0.001). HSCORE value was significantly higher in stimulated cycles for both integrins.Endometrial integrin expression is more consistently present in the early luteal phase in stimulated cycles than in natural cycles and this may be related to the higher serum progesterone concentration and/or the more advanced endometrial histological features.