Menstruation once every two months, as long as the existence of normal ovulation, will not cause the impact of fertilization, menstrual cycle, follicular development is closely related to the regularity of follicle development, when the follicle enters the stage of rapid development until maturity discharged, probably half a month, after the exclusion of the formation of the corpus luteum and can be maintained for fourteen days, the corpus luteum of the follicle in the process of secretion of estrogen and progesterone in the role of the uterus endometrium, the occurrence of cyclic hyperplasia, The luteum of the follicle can secrete estrogen and progesterone and act on the endometrium, which undergoes cyclic proliferation and secretion. At this time if you want to prepare for pregnancy you can monitor the follicles to determine whether there is a mature follicle, if there is nearly likely to be in the ovulation period for intercourse, the chances of pregnancy will be greater. However, delayed menstruation and early menstruation can potentially cause some diseases, such as endocrine hormone disease polycystic ovary prolactinemia, including thyroid hormone, insulin resistance abnormalities, so this time to carry out a detailed assessment of whether there is the existence of these endocrine hormone diseases.