Menstrual cycle: Phases and your fertility

menstrual cycle

by Lorna White |

As with most things to do with our bodies, there's a lot more to be aware of that just the things we learned in biology. Especially if you're trying to conceive, it's important to get to know what's normal for you by tracking your menstrual cycle to know when you're ovulating and when your fertile window is.

To help you find out more about the menstrual cycle, and the different phases your bodies go through, we've put together a simple guide to help you get to know your body better.

What is the menstrual cycle?

The menstrual cycle refers to the is the monthly cycle of changes a woman's reproductive organs go through in preparation for pregnancy. The menstrual cycle is controlled by our hormones and happens in four phases.

Menstrual cycle phases

The four phases of the menstrual cycle are: menstruation, the follicular phase, ovulation and the luteal phase.

Menstruation - This is your period, and we experience vaginal bleeding when the thick lining of the uterus falls away. This blood contains this lining, cells and blood. Periods can last anywhere between three days and a week.

Follicular phase - This starts on the first day of menstruation and ends with ovulation. This is where the pituitary gland releases follicle-stimulating hormone (FSH) which stimulates the ovaries to produce follicles and each follicle houses an immature egg. Usually, only one follicle will mature into an egg, while the others die. This usually occurs around day 10 of a 28-day cycle. The growth of these follicles stimulates the lining of the uterus to thicken in preparation for a possible pregnancy.

Ovulation - This is when the egg is released from the surface of the ovary. This happens around two weeks or so before menstruation starts. Your bodies hormonal changes cause the egg to be funnelled into the fallopian tube and toward the uterus by waves of small, hair-like projections. The life span of the typical egg is only around 24 hours unless it meets a sperm during this time, it will die.

Luteal phase - If the egg doesn't get fertilised, it will die at usually day 22 in a 28-day cycle and cause the cycle to begin again with menstruation.

How long is the menstrual cycle?

Like everything when it comes to our bodies, we are all different. And while we get taught that women should get their periods every 28 days, it's totally normal for our cycles to be anywhere between 21 to 40 days.

As you age, it's likely your cycles will become shorter. Your period might also change to be lighter, heavier, shorter or longer. You might also experience more or less period pain, and what is normal for you can change.

If you're on contraception, it's likely your menstrual cycle will change as a result, so it's worth speaking to your GP about how your kind of contraception might affect your menstrual cycle.

Although your periods can become more irregular during the menopause, it's important to speak to your doctor if you're experiencing anything that isn't normal for you.

Menstrual cycle hormones

The menstrual cycle is a very complex cycle, controlled by a huge range of different hormones. It starts with the hypothalamus, which causes the pituitary gland to release follicle stimulating hormone (FSH). Before ovulation, your oestrogen levels will rise, which prompts the release of a chemical called gonadotrophin-releasing hormone (GnRH), then prompting the pituitary gland to produce raised levels of luteinising hormone (LH) and FSH, causing ovulation.

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