a natural, repeating rhythm
the menstrual cycle is one of the most consistent processes the body carries out, month after month, from the first period in adolescence through to the menopause. understanding how it works can make it easier to notice what is normal for you, spot changes early, and feel more at ease with your own body.
at its simplest, the cycle is the body's way of preparing for a possible pregnancy each month. if pregnancy does not happen, the lining of the womb is shed as a period, and the whole process begins again. this is counted as one menstrual cycle, and it is driven by a carefully timed sequence of hormones produced by the brain and the ovaries.
the four phases
although every body is a little different, the cycle is generally described in four overlapping phases:
- menstruation: the shedding of the womb lining, experienced as a period.
- the follicular phase: the ovaries begin developing follicles, each containing an egg, while the womb lining starts to rebuild.
- ovulation: a mature egg is released from the ovary.
- the luteal phase: the body prepares for a possible pregnancy, and if this does not occur, the cycle starts again with a new period.
menstruation and the follicular phase actually overlap, since the follicular phase begins on the first day of the period and continues until ovulation.
how long does a cycle last?
a cycle is counted from the first day of one period to the first day of the next. cycles often range from around 21 to 40 days, and it is common and normal for length to vary somewhat from month to month. what matters most is understanding your own typical pattern, rather than comparing yourself to a fixed "textbook" number.
why hormones matter
the whole cycle is coordinated by hormones, including oestrogen, progesterone, follicle stimulating hormone (fsh) and luteinising hormone (lh). these rise and fall in a predictable sequence, triggering ovulation, supporting the womb lining, and eventually signalling menstruation if pregnancy has not occurred. these hormonal shifts can also influence energy, mood, skin, digestion and sleep, which is why many people notice a pattern to how they feel across the month.
getting to know your own cycle
because every body is different, there is a wide range of what counts as a normal cycle. tracking your cycle over a few months, whether with a diary, an app, or simple notes, can help you get familiar with your own pattern and notice if something changes.
if your cycles are consistently very irregular, unusually painful, or accompanied by symptoms that worry you, it is always worth speaking with a healthcare professional. they can help rule out underlying causes and offer personalised advice and support.
over the rest of this content hub, we will look at each phase of the cycle in more depth, along with the hormones behind them, so you can build a clearer picture of what is happening in your body throughout the month.