Body · cycle · fertility
Understand your menstrual cycle
Understand what happens, learn which signs your body may give you and discover how to recognise your own patterns.
The menstrual cycle is more than your period. It runs from the first day of bleeding, through the development of an egg and possible ovulation, to your next period. Understanding this basic pattern can help you make sense of what you notice in your own body.
01 · Explore the cycle
First: see the whole cycle
Your cycle starts on the first day of your period. It is usually divided into two main phases: the follicular phase before ovulation and the luteal phase afterwards. We also show your period and ovulation as separate stages to make the process easier to understand.
01
Period
Day 1 begins a new cycle
Oestrogen and progesterone levels are low, and part of the uterine lining is shed as menstrual bleeding.
02
The follicular phase
From your period to ovulation
FSH helps follicles develop in the ovaries. Oestrogen rises and the uterine lining builds up again.
03
Ovulation
An egg is released
A surge in LH triggers ovulation. The timing varies and does not necessarily fall on day 14.
04
The luteal phase
From ovulation to your next period
Progesterone becomes important. If pregnancy does not occur, hormone levels fall and a new period begins.
28 days is an example, not a rule
For adults, a cycle of around 25 to 35 days is within the usual range. In teenagers, cycles can be more irregular during the first years after their first period. The time before ovulation may vary considerably, while the time between ovulation and the next period tends to be more consistent.
02 · What drives the cycle?
Hormones work together
The brain and ovaries communicate through hormones. You do not need to memorise their names, but knowing them can help explain why your body changes during your cycle.
FSH
Follicle-stimulating hormone
FSH is released by the pituitary gland and stimulates follicles in the ovaries to develop. Each follicle contains an egg cell.
Oestrogen
Rises before ovulation
The follicles produce oestrogen, which helps build up the uterine lining. When oestrogen reaches a high enough level, it helps trigger the signals leading to ovulation.
LH
The hormone surge before ovulation
A sharp rise in LH helps trigger ovulation. This is the hormone surge that ovulation tests are designed to detect.
Progesteron
Becomes important after ovulation
After ovulation, more progesterone is produced. It affects the uterine lining and usually causes a slight rise in resting body temperature.
03 · Learn the signs
Signs your body may give you
No single sign can tell you everything about where you are in your cycle. Looking at several signs together over time may help reveal a pattern.
01
Bleeding
The first day of proper menstrual bleeding is day 1. You can note how long you bleed and whether your bleeding changes over time.
02
Vaginal discharge and cervical mucus
Before ovulation, some people notice wetter, clearer, slipperier or more stretchy discharge. This is related to hormonal changes. Discharge alone cannot pinpoint when ovulation occurs.
03
LH
LH levels rise before ovulation. Ovulation tests measure this rise in urine and can indicate that ovulation is likely approaching, but they cannot guarantee that an egg is actually released.
04
Basal body temperature
Resting body temperature usually rises slightly after ovulation due to progesterone. Temperature tracking is therefore most useful for identifying afterwards that ovulation probably occurred, rather than predicting it on its own.
05
Other things you may notice
Some people notice mild pain around ovulation, tender breasts, bloating, mood changes or differences in sleep or energy. Others notice very little. There is no single set of symptoms everyone experiences.
Your body does not have to follow a phase programme
Some people notice clear changes in mood, energy or physical performance throughout their cycle; others do not. There is no fixed week when everyone automatically performs better or worse. Use your observations as information, not rules about how you should feel or what you should be able to do.
04 · Make this knowledge your own
Find your own pattern
You may not understand your own cycle after just one month. The goal is not to control your body. It is to gather enough information to recognise what is usually normal for you.
Mark day 1
Write down the first day of proper menstrual bleeding. When your next period starts, you can work out the length of that cycle.
Choose a few signs
Track what you actually want to understand, such as bleeding, discharge, pain, mood or temperature. You do not have to record everything.
Look for recurring patterns
After a few cycles, you may notice whether something tends to occur at a similar point in your cycle and then goes away.
Notice changes
Your cycles do not have to look perfect. Focus on what is usual for you and whether anything changes suddenly or noticeably.
A simple example
This may be enough to track
You can also include basal body temperature or LH tests if you use them. They are not necessary for learning the basic pattern of your cycle.
What can an app tell you?
An app can store your entries and estimate likely dates based on earlier cycles. Calendar data alone cannot tell you exactly when you ovulate. Predictions are particularly uncertain when your cycle length varies.
05 · Fertility
Pregnancy can be possible on several days around ovulation
An egg can be fertilised for a short time after ovulation, while sperm may survive in the body for several days. This means the fertile window extends beyond the day of ovulation itself.
If you want to become pregnant
Learn when fertility may be higher
Cycle length, changes in cervical mucus, LH tests and temperature provide different kinds of information. An LH surge can suggest ovulation is approaching, while a temperature rise is usually seen after ovulation.
You do not have to time one perfect day. Because sperm may survive for several days, sex in the days before ovulation can also lead to pregnancy.
If you want to avoid pregnancy
Knowing your cycle is not the same as reliable contraception
Counting days or using an app to estimate ovulation does not provide reliable contraception on its own. Fertility-awareness methods require systematic tracking of specific signs, proper instruction and consistent use.
Condoms are also important if you need protection against sexually transmitted infections.
Hormonal contraception changes the pattern
Hormonal contraception may affect or suppress ovulation and change bleeding patterns. This means the same signs may not reflect a natural cycle. It is more useful to understand how your specific method affects your body and bleeding.
When should you ask for help?
Changes can provide useful information
Speak to a healthcare professional if period pain significantly affects everyday life, if you have very heavy or prolonged bleeding, your periods stop for an extended time or your pattern changes noticeably, or if recurring physical or emotional symptoms are difficult to manage. You can also ask simply because you are unsure.
Sources
The information is based on reliable resources about the menstrual cycle and fertility awareness. Sources open in a new tab.
One place to start
When your next period starts, mark day 1
Choose one or two things you want to track. When your next period begins, you will have one complete cycle to look back on. After a few cycles, you may start to recognise your own pattern.
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