Ultrasound assessment of the endometrium and the window of implantation.

In assisted reproduction techniques, the endometrium is ultrasonographically controlled and prepared to receive the embryo in the best conditions. In general, the endometrium is suitable to receive the embryo when its appearance is trilaminar and its thickness is about 7-10 mm.

However, it is also possible to perform an endometrial receptivity test to check whether the window of implantation is displaced or not. This ensures that the embryo transfer is performed when the endometrium is receptive.