The Menstrual Cycle – Ovulation and Menstruation

The menstrual cycle is approximately 28 days although in some women, it can be as short as 22 days or as long as 35 days. This is calculated from the first day of one period to the first day of the next period. Women with a cycle shorter or longer than these time may have issues with fertility. Refer to the causes of female infertility for more information.

The two most noticeable events during the menstrual cycle is ovulation and menstruation. Ovulation is the time when the ovary releases the egg cell (ovum). Menstruation is when you are having your period. Here the body ejects the inner lining of the uterus, known as the endometrium.

The entire menstrual cycle is coordinated by changing hormone levels.


Ovulation occurs approximately 14 to 16 days before you have your period. The pituitary gland in the brain secretes two hormones – follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These hormones then stimulate the ovary to release an egg cell into the fallopian tube. The ovaries also begin to produce high amounts of oestrogen at this time.

Once the egg cell is released, the ovary also begins releasing progesterone. Oestrogen and progesterone prepares the endometrium for implantation of embryo. The embryo forms when an egg cell is fertilized by a sperm cell. If this occurs, then you are pregnant and the embryo will attach to the inner lining of the uterus so that the foetus can grow.

However, if fertilization does not occur (no pregnancy), then the levels of oestrogen and progesterone drop. This prepares the endometrium for menstruation.

Refer to the online ovulation calculator for an estimated date of ovulation.


Menstruation is the process where the body ejects the contents of the uterus. Once oestrogen and progesterone levels drop, the endometrial lining begins to slough (shed). This is then passed out as your menses (period).

Your period may last between 3 to 7 days. There may be some discomfort and mild cramping but a painful period is not the norm. If you are experiencing severe period pain, then you need to see a gynaecologist.

Once you finish your period, all the hormones that control the menstrual cycle return to a normal level and the body prepares for the next period of ovulation.