An ERA is an endometrial receptivity array. It is a test that claims to find the optimal time for an embryo to be transferred into a woman’s uterus in order for the embryo to implant, known as the “window of implantation.” It is typically meant for women who have had one or more failed embryo transfer cycles. The test can help determine the next window for implantation down to a 6 hour window therefore increasing the likelihood of implantation and pregnancy.