The menstrual cycle

The idea

Ovulation, preparation of the uterus and menstruation repeat every 21–35 days (often 28) from puberty to menopause; in a 28-day cycle, menstruation is days 1–5, ovulation day 14, then the lining thickens.

A repeating pattern

The events of ovulation, the thickening of the uterine lining and menstruation happen again and again, in a pattern.

How often do you think the pattern repeats?

• Typically every 21 to 35 days
• Every day
• Once in a year

Move through the days

Move the slider along an example 28-day cycle.

Days of the cycle

In a 28-day cycle, menstruation takes days 1 to 5, then the lining rebuilds, the egg is released on day 14, and the lining becomes thick again. The cycle repeats from puberty to menopause.

Ovulation, preparation of the uterus and menstruation repeat every 21 to 35 days (often 28) from puberty to menopause. In a 28-day cycle, menstruation is days 1 to 5, ovulation day 14, then the lining thickens.

Notes

The cycle of ovulation, uterus preparation and menstruation repeats every 21 to 35 days (often 28): days 1 to 5 menstruation, day 14 ovulation.

Check yourself

In a 28-day cycle, on which day does ovulation take place?

Answer: 14

Ovulation takes place on day 14 of a 28-day cycle.

In a 28-day cycle, menstruation is on…

How often does the cycle typically repeat?

The cycle usually begins at puberty and continues until…

• days 1 to 5 — correct. Yes!
• days 15 to 28. In these days the uterine lining becomes thicker and rich with blood vessels.
• day 14 only. Day 14 is ovulation, when the ovary releases a mature egg.
• Every 7 days. The cycle typically repeats every 21 to 35 days.
• Every 21 to 35 days, often around 28 days — correct. Yes!
• Every 90 days. The cycle typically repeats every 21 to 35 days, often around 28.
• the age of 20. It continues till menopause, around age 50.
• the age of 14. The cycle usually begins between the ages of 10 and 14 and continues till menopause.
• menopause, around age 50 — correct. Yes!