During the menstrual cycle the uterus prepares itself for implantation of a fertilised egg. If this does not happen then the uterus will shed its lining and this is known as menstruation or a “period”.

Usually the menstruation cycle is between 28–35 days. On day 1, the cycle begins with bleeding and this usually lasts 3–7 days. The cycle ends just before the next menstrual period.

The menstrual cycle is carefully regulated by several hormones. Luteinizing Hormone (LH), Follicle-stimulating Hormone (FSH), Estrogen and Progesterone.

The cycle is divided into three phases:

The first phase is before the egg is released

The second phase is ovulation where the egg is released

The third phase is after release of the egg


This phase is the first day of bleeding when the egg is not fertilized and the lining of the uterus begins to shed. In this phase, estrogen and progesterone levels are low. You will probably be feeling more tired during this phase.

The pituitary gland starts to increases production of FSH and estrogen is secreted to stimulate the egg cells in the ovaries to grow and mature. This takes about 13 days. You will have a boost of energy during this phase and its a good time for exercise as you will have more testosterone. You might also find that you have new ideas, feel motivated to have a clear out or tidy up and help out others too. This is a good time to start new projects. This phase ends with ovulation.


The pituitary gland now increases the production of LH. This usually happens on day 14 and tells the ovaries to release the egg into the fallopian tube. The lifespan of the egg is usually about 24 hours unless it is fertilized by sperm. At this time, estrogen and testosterone drop off and progesterone is released. The corpus luteum keeps progesterone levels high to maintain the lining of the uterus.


If pregnancy does not occur, progesterone reduces at around day 22 and around day 28 the next menstruation period begins.


After the age of around 35, the hormones, estrogen, progesterone and testosterone start to go up and down like on a rollercoaster ride. This is just a guide as the signs will be subtle at first, some women don’t really notice any real changes until well into their 40’s. These hormone changes will have an impact on your menstruation cycle. Progesterone is the first hormone to start declining during perimenopause.

As you get older, your ovaries age too and your eggs start to run out. Your ovaries start to produce less and less estrogen and progesterone and as a result, your pituitary gland secretes higher levels of FSH and LH to enable your body to keep your ovaries working like they used to and continue to develop follicles, produce estrogen and after ovulation, produce progesterone. The increase will keep the ovaries ticking over but before long, the levels must continue increasing in order to get the job done and the FSH and LH will start failing in the production of enough estrogen and progesterone. Estrogen levels will begin to decline much closer to menopause .

Due to the hormone changes, you will start to have some symptoms such as hot flashes, mood swings, anxiety etc. The good news is that there are lots of ways to control your rollercoaster ride of hormones and get your symptoms under control. You do not have to put up with them and accept it as a “natural process of ageing”.

In the early stages of perimenopause, you can expect to start noticing changes in your period. Your cycle will probably start at day 25 instead of day 28, you will most likely notice that the flow is different, sometimes heavier, sometimes lighter, your periods become more irregular and you might go a few months without a period. As you get closer to menopause, you will notice that you will skip more and more periods each month. This is a normal process and the larger the gap between periods the closer you are getting to menopause.

Perimenopause is over when you have gone a full 12 months without a period. You are then in menopause. When you hit menopause and your ovaries have closed down, your adrenal glands take over in production of your hormones.

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Andrea Howard

Originally published at medium.com