What is a Menstrual Cycle?

A menstrual cycle is the intricate play of hormones that rise and fall over the course of a number of days (typically 24-36), stimulating ovulation and the growth of the uterine lining in preparation for a potential pregnancy (whether we want to get pregnant or not). 

Ovulation is the central event of our cycle and menstruation marks the start of each new cycle.

This rise and fall of hormones actually starts in the brain, with the hypothalamus, which then tells the pituitary gland to make FSH and LH. These hormones in turn stimulate the ovary to produce oestrogen and progesterone.

This is known as the Hypothalamic-Pituitary-Ovarian (HPO) axis and it is responsible for the regulation of our menstrual cycle.

Do you know your horomones?

• GnRH: Produced by the hypothalamus and signals the pituitary gland to produce FSH & LH.

• FSH: Stimulates immature eggs within their own follicle (sacs) to mature and grow. 

• LH: Stimulates the release of the mature egg from the follicle - eg. ovulation.

• Oestrogen: Produced by the growing follicle in the ovary. Dominates the first half of the cycle. 

• Progesterone: Produced by the corpus luteum. The corpus luteum is a gland that forms from the empty follicle once ovulation has occurred.

• Testosterone: Important for bone and breast health. Helps build muscle mass.