Menstrual cycle is a must for woman to be able to produce children of her own. In female anatomy menstrual cycle is a recurring phase of physiologic changes that takes place in the reproductive-age category.
Menstrual cycle starts in a woman at the average age of 12 and goes on until she is 50+. It is considered normal to happen anywhere between the age of 8 and sixteen. The beginning of menstruation is called `menarche.
This routine of menstrual cycle takes place every 28 days all through between puberty and menopause.
We humans undergo what is called the Overt Menstruation, i.e. menstruation involving blood flow from vagina.
This is a process seen exclusively in humans, and animals like the chimps with whom humans share a close evolutionary relations.
Other than humans and chimps other female mammal species undergo covert menstruation in which the endometrial is reabsorbed by the animal at the conclusion of reproductive cycle.
The entire cycle is divided into several phases.
1- Menstrual phase is the first phase lasting 1-4 days in an average person.
2- From day five to thirteen is called the follicular phase;
3- 14th day is considered the day for ovulation, the most important day for couples trying to conceive;
4- from day fifteen to twenty six it’s called the luteal phase.
5- And last two days i.e. 27th and 28th day is considered ischemic phase.
Different phases point towards different pdevelopmental stages in the reproductive system. Post first four days when menstruation is in progress and the woman is bleeding, phase two begins.
With the onset of follicular phase i.e. from day five to day thirteen from the start of period, the uterus lining starts the process of thickening; at the same time there is an increased secretion of amounts of estrogen which takes place at a steady pace.
In this phase follicles in the ovary start developing influenced by a complex and intricate working of hormones, and towards the end of this phase one or two follicles become dominant, remaining die.
These strong follicle releases an egg called the ovum in medical language, on the fourteenth day called the day of ovulation. (An egg that is fertilized by a motile sperm cell will take form of a zygote, and it will take zygote a few days to shift and move towards the fallopian tubes to finally plant itself in the uterus.
If the egg does not get support of motile sperm and does not get fertilized in a day post ovulation, it will die a natural death and get absorbed by the woman’s body.)
Post ovulation the remaining follicles also meet the same end. They die.
At this time progesterone, which is produced by body at this time, starts becoming active, during the same period, the endometrial or uterine wall lining also becomes stronger and thicker to get ready to support embryo for probable implantation assuming that the woman will conceive in the cycle.
However if implantation does not take place within two weeks, the follicle as already mentioned dies; this brings a sudden drops in estrogen and progesterone levels, which in turn leads to drop in hormone and this chain reaction causes the uterus to shed its lining and blood starts to ooze out and is termed as start of menstruation cycle and this is what the beginning to the first day of next new cycle is all about.
Menstrual cycle is controlled hormonally and is a must for women to be able to reproduce. Menstrual cycle as mentioned earlier under normal cycle comes every 28 days in a healthy and normally ovulating woman. And the first day is counted from the day menstruation starts, because its onset of fresh hormonal movement.
Menstrual cycle post pregnancy can be erratic and may take anywhere between 3 and six months to normalize.
Some women also bleed heavily post delivery and experience cramps and PMS but these symptoms get rectified by themselves once body resumes normal functioning.
Periods delay during this time also because the new mother’s body is trying to accommodate breast feeding into the routine and it is pretty new experience for the woman as well the body.
Menstrual cycle is considered abnormal when it lasts more than 7 days; or comes before 20 days or later than 35 days or there is heavy blood flow. Doctor’s appointment should be seeked in such situations to know the cause of irregularity and resolve the issue at the earliest.