The Mensuration (Menstrual Cycle), is the scientific term for the physiological changes that occur in women for the purpose of sexual reproduction. During this period, the woman bleeds from her uterus via the vagina. The cycle consists of 28+/-7 days and is under the influence of hormones. The cycle is divided into the following phases-
- Follicular phase
- Ovulatory phase
- Luteal phase
Follicular phase– This phase begins from the time when menstruation commence and is followed by growth and thickening of the endometrium. This lasts for 10-14 days starting from the first day of menstruation. Oestrogens and progestrogens are at the lowest during menstruation. After the bleeding stops, proliferative phase (other name for follicular phase) begins, causing the endometrium to thicken in preparation for pregnancy. During the next two weeks FSH levels rise causing maturation of several ovarian follicles (small sacs in which the egg/ovule matures).
Ovulatory phase– FSH signals ovaries to produce oestrogens which stimulate LH to surge around fourteenth day, triggering one of the follicle to burst and release the largest egg.
Each cycle, a mature egg/ovule is released and can only be fertilized for up to 24 hours. The number of eggs released can vary from cycle to cycle, sometimes several eggs are released, which explains multiple births. The egg enters the fallopian tubes by the fimbrial movements.
Luteal phase– the ovulatory phase is followed by the Luteal Phase, also called the pre-menstrual phase. This lasts for approximately 14 days. After Ovulation the ruptured follicle develops into Corpus Luteum which produces Progestrogen. Oestrogens and Progestrone both simulate the endometrium to prepare a thick blanket of blood vessels which will support the fertilized ovum if pregnancy occurs.
When pregnancy occurs, this becomes the placenta. In absence of pregnancy, the corpus luteum deteriorates and becomes Corpus Albicans. Once this occurs the levels of oestrogens and progesterone decrease and the endometrial lining is shed during menstruation.
Average amount of blood lost during the period is 35ml. The women have pain in the lower abdomen at the time when period starts. Some experience pain before the periods. At time there are cramps in the abdomen in the middle of the periods that is at the time of ovulation. There may be increased discharge per vaginum at the time of ovulation or before the periods begin. ‘Arey itni saari medicine padha di hai, yeh kitaab hai ya aafat!’ (it is so troublesome to learn so much about medicine)– no all this is going in your body and will continue year after year till you will attain menopause (the time when your periods will stop.