However, in the present context it seems most useful to begin with the growth of the egg (ovum) and the gradual thickening of the uterine lining (endometrium).

• 但是，从月经周期生理变化的相互关系来看，以卵子生长和子宫内膜逐渐增厚来开始计算它的周期似乎最为适当。