Menstrual Cycle


Q.21. Discuss the menstrual cycle in short?

Ans. Menstrual cycle denotes the cyclic changes in a frigidity in woman under the influence of gonadotrophic and law and sex hormones from the onset of periodic bleeding or menstruation to the beginning of next menstruation occurring from menarche to menopause except during pregnancy and initial months of lactation. Menarche begins at about 13 years and menopause lasts till about 48 years of age in a woman. The initial and last few menstrual cycles are irregular. There is normal and regular menstrual cycle from 15 1045 years of age in most human sex  females. The average menstrual cycle is of 28 days but may vary from 21 to 35 days.

The menstrual cycle comprises of six phases as menstruation phase, resting phase, proliferative phase, ovulation, secretory phase and regression ‘phase. Menstruation phase is the first stage marked by monthly bleeding or menstruation or menses and last for 3-5 days. Menstruation occurs as a result of sudden withdrawal of female sex ethics hormones and when there is no fertilization of ovum during ovulation in the last menstrual cycle. About 35- 40 ml of blood is lost during one menstruation phase. Resting or regenerative or post menstruation phase is for about two days from fifth to sixth day of menstrual cycle with rise in F.S.H. level. The proliferative or oestrogenic phase varies in length and lasts for about a week from seventh day till ovulation with rise in level of oestrogen, FSH and LH. Ovulation is the shedding of ovum from the ovary and takes place at 14 + 1 day prior to the onset of next menstruation. Ovulation occurs every month alternately from each ovary when vagina secretes thin mucous and sexual hidden desire increases. Pregnancy occurs if stages of intercourse is done from three days prior to ovulation up to one day after ovulation. There is sudden fall in body temperature of about 0.5° F and then rise of about 0.5° F from normal temperature just before and after ovulation. Secretory or progestational or luteal phase lasts for 12 days from the time of ovulation to two days prior to the end of menstrual cycle with rise in level of L.H, progesterone and oestrogen. Regression or premenstrual phase is the last sixth phase of menstrual cycle and lasts for two days. The level of oestrogen, progesterone and LTH fall leading to gradual rise in level of FSH and is marked by pre-menstruation tension.