Pinkishe Foundation
31/10/2026
Dr. Shehla Jamal
The menstrual cycle is the monthly series of changes the body goes through to get ready for a possible pregnancy. It starts on the first day of one period and ends the day before the next one begins. The period itself is only one part of the cycle.
The cycle is run by hormones that pass messages between the brain, the ovaries and the womb (uterus). For adults, a cycle of 21 to 35 days is normal. In the first few years after periods start, cycles of up to 45 days are common. Your cycle can also change at different times of life, from your first period to menopause.
This is your period. If no pregnancy has begun, the hormones oestrogen and progesterone fall. The thick lining of the womb is no longer needed, so it sheds and leaves the body through the vagina, as a mix of blood, mucus and tissue.
A period usually lasts two to seven days. Cramps, sore breasts, bloating, tiredness, headaches, low back pain and mood changes are common.
This phase starts on the first day of your period, so it overlaps with it, and ends at ovulation. The brain releases a hormone called FSH (follicle-stimulating hormone). This prompts several small sacs in the ovary, called follicles, to grow. Each holds an immature egg. Usually one egg matures fully.
The growing follicle makes oestrogen, which builds up the lining of the womb again. The length of this phase varies more than any other, and it is the main reason cycle lengths differ from person to person.
Rising oestrogen makes the brain release a burst of another hormone, LH (luteinising hormone). This makes the ovary release the mature egg. This is ovulation.
Ovulation usually happens about 12 to 16 days before your next period. In a 28-day cycle, that is around day 14. The egg travels down the fallopian tube. The egg lives for about a day. If sperm meet it in that time, it can be fertilised.
Around ovulation, many people notice more discharge that is clear, wet and stretchy, like raw egg white.
After ovulation, the empty follicle becomes a small structure called the corpus luteum. It makes progesterone, which keeps the lining of the womb thick and ready.
If a pregnancy begins, the body makes a hormone called hCG. This is the hormone that pregnancy tests detect. If there is no pregnancy, the corpus luteum shrinks, hormone levels fall, and your next period begins.
Many people have PMS (premenstrual syndrome) in this phase, such as mood swings, bloating, sore breasts, food cravings or poor sleep. The luteal phase usually lasts about 14 days.
Noting the first day of each period, and how you feel through the month, helps you:
You can mark the dates on a calendar or a notes app, or use our period and ovulation calculator. Whatever you use, write down symptoms too: pain, heavy days, mood changes.
You are most likely to get pregnant in the five days before ovulation and on the day of ovulation itself, because sperm can live in the body for up to five days. But ovulation can shift from month to month, so there is no fully "safe" day. Do not rely on cycle tracking alone to avoid pregnancy. If you want to avoid pregnancy, talk to a doctor about contraception.
Some conditions change the cycle. PCOS often causes irregular or missed periods. Endometriosis often causes severe period pain. Thyroid problems can make periods heavier, lighter or irregular. A record of your cycle helps a doctor find the cause.
Have a question about your period? Call our menstrual helpline on 85888 70999. It answers at any hour.
A simple printable sheet that marks your period days, your fertile window and your ovulation day. We will email it to you now.
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Prefer to work out your dates now? Open the free ovulation calculatorIt is the monthly series of hormonal changes that prepare the body for a possible pregnancy. It runs from the first day of one period to the day before the next.
For adults, 21 to 35 days. In the first few years after periods start, cycles of up to 45 days are common.
The menstrual phase (your period), the follicular phase, ovulation and the luteal phase.
Usually about 12 to 16 days before your next period. In a 28-day cycle, that is around day 14.
No day is fully safe, because ovulation can shift and sperm can live for up to five days. If you want to avoid pregnancy, talk to a doctor about contraception.
Tracking helps you plan for your period, notice changes early, and give your doctor clear information if something is wrong.
Pinkishe Foundation is a specialist implementation organisation for menstrual health. We deliver, reliably, in schools and communities across India. Support our work with a donation.
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