What changes are observed in the uterus if fertilisation does not occur?

What changes occur in the uterus if fertilization does not occur? OR What happens to the human egg if fertilization does not occur?

What changes are observed in the uterus subsequent to implantation of young embryo?

What changes are observed in the uterus subsequent to implantation of young embryo?

What changes are observed in the uterus subsequent to implantation of young embryo?

Internal fertilisation occurs in

Internal fertilisation occurs