Transplantation of two blastocysts into three chorionic villi and three lambs may be the result of splitting of one of the transplanted eggs, or coitus fertilization before transplantation. Generally speaking, the egg remains in the cleavage stage for 72 hours after fertilization, and because of its totipotency, it is able to split into two separate fertilized eggs, which means that a monozygotic twin embryo with two chorionic chorionic villi and two lanugo membranes is formed. In addition, in a small number of women, if they conceive naturally by intercourse before the embryo transfer, then the embryo transfer will result in a triple chorionic and triple lambda situation. Generally speaking, in this case, fetal reduction is needed to minimize the risk of pregnancy and to achieve a better pregnancy outcome. It is recommended to consult a doctor if necessary.