Menstruation is a monthly cyclic, physiological shedding of internal lining of uterine cavity due to invisible interplay of female hormones. In simple terms, it is a regular monthly bleeding which a woman experiences. The first menstruation occurs usually at the age of 12 – 15 years. It is also called as ‘menarche’.
Once, the menstruation starts, it continues cyclically at an interval of 22 – 35 days with a mean of 28 days. Physiologically, it stops during pregnancy and lactation. Ultimately, it ceases between the ages of 45 – 50 years when menopause sets in. The duration of menstruation (menses) is about 4 – 5 days and the amount of blood loss is estimated to be 20 – 80 ml with an average of 50ml. The menstrual discharge consists of mainly a dark altered blood, mucus, vaginal epithelial cell fragments of endometrial, prostaglandin, enzymes and bacteria. Usually, at the mid scale, a mature egg is released (ovulation). If it gets fertilized, the menses ceases. Thus the absence of menstruation suggests that pregnancy has occurred.
Fertilization is a process of meeting (after mating) of the sperm with a mature egg. It begins with sperm egg collision and ends with a formation of life called zygote (single mononucleotide cell mass). The ovum immediately following ovulation is picked up by the fibril end of the fallopian tube and is rapidly transported to the ampullary part of the tube. Out of hundreds of millions of sperms deposited in the vagina after intercourse, only thousand specialized sperms enter the uterine tube while only 300 – 500 reach the egg. Out of this elite community, only one lucky member is allowed to get into the mature egg. The sperm either contains (22 X) or (22 Y) pattern of chromosomes while the egg contains 22 X only. The love of the child is determined by the pattern of the love chromosome supplied by the sperm. If the sperm contains (22 X) a girl child (46 XX) is formed, if it contains (22 Y) a boy child (46 XY) is formed.
The fertile period is period around ovulation, during which if relations are kept, the chances of pregnancy are high. In order to improve the chances of pregnancy, it is important to understand how to calculate the fertile period.
Calculation of a fertile period:
Mark the day 1 of your menses on a calendar. Do this for next 6 -8 cycles. Note the length of the longest cycle and shortest cycle. Subtract 18 from the length of the shortest cycle. Say you get a figure "X" .Subtract 11 from the length of the longest cycle. Say you get a figure "Y". So the period you obtain between "X" and "Y" is the fertile period.
For e.g. your shortest cycle is of 28 days, and the longest cycle is of 30 days.
so your fertile period is from the 10th day to 19th day.
As you know, the ovulation occurs approximately 14+ or -2 days before the next menstrual period. So the highest fertility period is around ovulation time i.e. mid cycle. The life span of the mature egg is approximately 48 hours. while the life span of the sperm is approximately 72 hours. So even when the relations are kept on day 10 or 11 of the menstrual cycle success can be achieved.