MICROANATOMY

Detailed explanation-1: -Menstrual cycle occurs due to rupture and shedding of the endometrium lining of the uterus. When an ovum gets fertilised the endometrium gets thickened, and vascularized to house the embryo. So during the whole term when the embryo/foetus is in the uterus, menstrual cycle stops temporarily.

Detailed explanation-2: -The main purpose of the luteal phase is to prepare your uterus for a possible pregnancy. During this phase of your cycle, an egg travels from your ovary through your fallopian tube and to your uterus. If sperm fertilizes that egg, the fertilized egg implants into your uterine lining and pregnancy occurs.