This is day 2 of your menstrual cycle

Understanding how your menstrual cycle works and keeping track of it may improve your chances of conceiving.

278 days until your due date

Your cycle runs from the first day of one period to the first day of the next. The average is 28 days, but many women have shorter or longer cycles.

Bleeding is often heaviest around now as the uterus lining (endometrium) is shed. The average total loss is about 2 tablespoons (30 ml). Blood vessels in the uterus narrow as the lining comes away, which can cause cramping period pains.

Once your period ends, an egg starts to mature inside its follicle in one of your ovaries, ready to be released around the middle of the cycle (ovulation).

Meanwhile, estrogen and progesterone rebuild the uterus lining so it can receive a fertilized egg. If the egg isn't fertilized, hormone levels fall, the lining is shed, and the cycle starts again.

As a matter of fact

Periods can synchronize

Women who live or work together sometimes find their periods fall into step. Scientists suggest this happens because chemical signals called pheromones pass between women and are picked up by receptors in the nose, prompting one woman's cycle to adjust.

Explainer

Changes during the menstrual cycle

Over a 28-day cycle, an egg matures inside its follicle in the ovary and is released around day 14. Meanwhile, the uterus lining sheds during the period and then rebuilds, ready for a fertilized egg. After ovulation, the empty follicle (corpus luteum) produces progesterone, which helps the lining reach about 0.2 in (6 mm) thick. The cycle runs through four phases: the period, a relatively infertile phase, the fertile phase around ovulation, and an infertile phase until the next period.

This is general information based on NHS guidance, not medical advice, and every pregnancy is different. Talk to your midwife or GP about anything that worries you. If your baby's movements slow down or change, or you have bleeding, severe pain or leaking fluid, call your maternity unit straight away. In an emergency, call 999.