Phases of menstrual cycle
The advantage of knowing the menstrual cycle is mainly to understand when to conceive or not.
a) Proliferative phase: Immediately following a menstrual flow (occurring the first 4 or 5 days of a cycle), the endometrium begins to proliferate or grow very rapidly increasing in thickness to 8 fold its normal size. This increase continues for the first half of the menstrual cycle (from approximately day 5 to day 14). This half of a menstrual cycle is termed as the proliferative or estrogenic (follicular) phase (see Figure 1.8. below).
b) Secretory phase: Occurs during the next half of the menstrual cycle depending on whether or not the released ovum meets the spermatozoa and gets fertilised. If fertilisation does take place, the corpus luteum in the ovary begins to regress after 8 to 10 days of the start of the Secretory phase. This is because the production of progesterone and oestrogen decreases. That is, the withdrawal of progesterone stimulation degenerates the endometrium of the uterus (at approximately day 24 or 25 of the cycle). The capillaries rupture resulting in minute haemorrhage while the endometrium sloughs off both released through the birth canal causing menstruation.
