What is a Menstrual Cycle?
Menstrual cycle is a one month cycle, involves changees in hormones and physiology of female reproductive system. This changes prepares the uterus of female for pregnancy. If the fertilization (also called as pregnancy) occur then it MC ends. If it (pregnancy) does not occur then the prepared or thickened line of uterus is shed out/ eliminate out from body via vagina, process called as menstruation, period, menstrual bleeding. The first day of period/ menstruation is the first day considered for next cycle.
An normal menstrual cycle ranges between 21 to 35 days.
What are the Phases of Menstrual Cycle?
There are four phases of menstrual cycle,
- Menstrual phase
- Follicular phase
- Ovulation phase
- Luteal phase
Menstrual Phase
It is the first phase of menstrual cycle. This stage is mark by both menstruation and initiation of new cycle. It involves removing out the shed of uterine lining and prepare reproductive cycle for next pregnancy. It occur in 1 to 5 day.
For menstruation in menstrual phase following changes occur,
- Hormones like estrogen and progesteron responsible for sustained pregnancy is reduced and bleed occur
- Thickened endometrial line break down in the uterine lining, and blood, mucous, endometrial tissues is expelled out through the vagina as period
- After bleeding, the uterine lining starts to rebuild
Changes related to new cycle,
- Follicle stimulating hormone (FSH) increases lead to form new ovarian follicles.
- Many ovarian follicles start to form and one of dominant follicle mature for next ovum
The symptoms women may feel are cramps, back pain, fatigue, and mood changes etc.
Follicular Phase
Follicular phase consider as 1st to 13 days. It starts frm the menstrual phase, overlapping it and start next phase.
This phase is mark by growth of follicles via FSH. This developing follicles starts to produce estrogen. It also helps to promote growth of uterine lining. High estrogen trigger LH (lutenizing hormone) towards end of phase, to start ovulation phase.
Chracteristics of Follicular Phase
- Follicles get develop and mature
- Estrogen level rises and strengthen the uterine lining
Ovulation Phase
Ovulation phase is 3rd phase characterized by release of ovum from ovaries. The ovum is viable for 12 to 24 houres for fertilization. It occur 14th day of menstrual cycle, as per the length of cycle.
At first, high Estrogen level trigger form lutenizing hormone, which breaks graffian follicle, release ovum from ovary. A female can feel mild abdominal pain, vaginal discharge, increased body temperature and sexual desire.
If egg get fertilize then preganancy starts. If no pregnancy happen then egg starts to degenerate and luteal phase starts.
Luteal Phase
Luteal phase is fourth and last phase of menstrual cycle. It start after day 14 to till 28.
The remaining portion of the graffian follicle converts into the corpus luteum. It produce progesteron and estrogen to maintain pregnancy till placenta takes over.
If pregnancy does not occur then corpus luteum degenerates to corpus albicans after 12 to 14 days. Then there will be decreased progesteron and estrogen level which causes breakdown of endometrium layer of uterus. There after bleeding occurs in menstrual phase.