The female uterus, or womb, has a lining in which an embryo is embedded following fertilization. This lining is what scientists refer to as the endometrial stripe.
Throughout the month, the endometrial stripe is a lining inside the uterus that grows until a woman undergoes vaginal bleeding as part of her menstrual cycle if she is not pregnant. However, if a child has been conceived in the past few days, the lining does not shed and, in turn, becomes home to the newly fertilized embryo. The endometrium is one of three layers inside the uterus, which is how the term "stripe" came about, because, when examined anatomically, the layers are formed on top of one another as if they are stripes.