Is the endometrial lining receptive?

For the embryo to implant into the uterus, the endometrium should be receptive. Factors that may interfere with implantation include:

• Inadequate levels of progesterone
• Absence of proteins (beta 3 integrins) which helps the embryo to stick to the uterine lining
• Irregularities of uterine lining like fibroids, polyps etc