The human females release one egg every month. The uterus also prepares itself every month to receive a fertilised egg. The inner uterus lining (endometrium) becomes thick and is supplied with blood to nourish the embryo. If the egg is not fertilized, then the uterus lining breaks down and is released in the form of blood and mucus through the vagina. Since the egg is not fertilised and is lost with the blood, it is known as funeral of the unfertilized egg or weeping of the uterus for the loss of ovum.