The period during which the lining of the uterus is most receptive to implantation is called the “implantation window”, which is generally 6 days after ovulation.
In rare cases, this implantation window can be a few days earlier or later. This can be determined by examining the endometrium (the lining of the uterus). For this, a small sample is taken at the usual time in the cycle, and genetic testing (ERA test) is carried out. If the implantation window is offset, the point of time for embryo transfer must be adjusted.