Every woman experiences her menstrual cycle differently, but everyone is controlled by her hormones. Your menstrual cycle starts on the first day of your period, and continues until the beginning of your next monthly cycle. On average, a woman’s menstrual cycle normally lasts for 28 days but it can be longer or shorter. Also, a woman who experiences a longer cycle will have fewer monthly period, while women with shorter periods may have more than one a month. No matter the length of your menstrual cycle, it is controlled by your hormones.
There are four main phases to the menstrual cycle, and each stage is controlled by different hormones. Here are the four stages and the effects that your hormones have one them.
Menstruation (The Menstrual Phase)
A woman’s menstrual cycle begins on the first day of her period. Menstrual blood, also referred to as menses, begins to leave the lining of the uterus when fertilization does not occur. The menses travels from the uterus through the cervix and vagina, to finally empty out of the vaginal opening. The blood can vary in color, from light pink to dark brown, and will usually last from 2-7 days. While some flows may be heavier or lighter, a woman generally only loses between 4-14 teaspoons of blood and fluid during her monthly period.
The Follicular Phase
The female hormone estrogen plays an important role in this phase of the menstrual cycle. Estrogen is what causes the lining of the uterus to grow and expand, in anticipation of nurturing a fertilized egg. The follicle stimulating hormone is also present during this time, and is tasked with helping the follicles to develop and release the female eggs. In the beginning stages of the follicular phase, the FSH hormone will help to stimulate several of the ovarian follicles, but by the end of this phase only one follicle will still be active.
As the estrogen levels begin to dramatically rise, the walls of the uterus will begin to thicken. Right before ovulation, a woman’s estrogen levels will be at their highest and will normally peak once a day. The sudden daily increase* in estrogen will also trigger the release of another female hormone, the LH or luteinizing hormone. As this hormone becomes more apparent, the last follicle will release the egg and another phase in the menstrual cycle will begin.
The Ovulation Phase
Once the follicle has released the egg, it will begin to travel down the fallopian tube. Women who experience a 28 day cycle will begin to ovulate around the 14th day of the menstrual cycle. On average, most women experiences ovulation between 11 to 16 days before menstruation starts. As the egg moves down the fallopian tube, the wall of the uterus will continue to thicken in anticipation of a fertilized egg. It can take up to four days for the egg to reach the uterus, but it must be fertilized within the first 24 hours of being released. If it remains unfertilized and ovulation ends, the next phase of the cycle will begin.
The Luteal Phase
Once ovulation has ended, estrogen and progesterone are still being produced. The follicle now changes, and becomes the corpus luteum which will begin to produce large amounts of these hormones. The higher levels of estrogen will continue to strengthen the walls of the uterus. If the egg is not fertilized, then the corpus luteum will begin to dissolve. Now that the hormonal levels are beginning to drop, the lining in the uterus will begin to dissolve and menstruation will soon begin again. It normally takes two weeks for the lining to completely dissolve and menses to start.
Throughout a woman’s life, she will release around 400 mature eggs, and this will occur through every menstrual cycle. Occasionally the hormonal levels can change, causing the menstrual cycle to become irregular. These hormonal imbalances can usually be easily corrected with a simple lifestyle change. Women who are trying to become pregnant should always pay close attention to their monthly periods, and report any sudden irregularities to their health care provider.
The female hormones estrogen and progesterone play an important role in the sexual and feminine health of a woman, and they can easily be disrupted. If you are experiencing or suspect that you might be suffering from an imbalance, see the advice of a health care professional. Part of living a healthy life is having a healthy and regular menstrual cycle.