The Menstrual Cycle

At birth, a girl has thousands of unripe eggs in the ovaries. At puberty, the eggs ripen at different times, and are released from each of the two ovaries in turn.
Ovulation takes place about once every 28 days.
After ovulation, uterus lining becomes thicker and well-supplied with blood vessels to prepare for development of fetus.
If the egg is fertilised by a sperm, the fertilised egg grows in the uterus. The ovaries then stop releasing more eggs until the baby is born.
If the egg is not fertilised, the egg dies in the uterus. The egg together with blood and thick uterus lining is then discharged through the vagina as menstrual flow.
A regular menstrual cycle lasts 28 days.

The Menstrual Cycle

In a cycle, ovulation usually occurs about 14 days before the next menstruation.
The fertile period is the 11th - 18th days of the menstrual cycle.

The Menstrual Cycle