What is the role of hormones in the menstrual cycle?

Hormones regulate the menstrual cycle by controlling the maturation and release of eggs and preparing the uterus for pregnancy.

Hormones play a crucial role in the menstrual cycle, which is a monthly process that prepares the female body for potential pregnancy. The cycle is regulated by a complex interplay of hormones, primarily oestrogen, progesterone, follicle-stimulating hormone (FSH), and luteinising hormone (LH).

The menstrual cycle begins with the follicular phase, during which the pituitary gland releases FSH. This hormone stimulates the growth of several ovarian follicles, each containing an immature egg. As the follicles grow, they start to produce oestrogen, which thickens the lining of the uterus, or endometrium, to prepare it for potential implantation of a fertilised egg.

Around the middle of the cycle, a surge in LH, triggered by the rising levels of oestrogen, causes the most mature follicle to burst and release its egg in a process known as ovulation. Following ovulation, the ruptured follicle transforms into the corpus luteum, which secretes progesterone. This hormone further prepares the endometrium for pregnancy by making it more glandular and vascular.

If fertilisation does not occur, the corpus luteum degenerates, leading to a drop in progesterone and oestrogen levels. This hormonal change triggers the shedding of the endometrial lining, or menstruation, marking the start of a new cycle.

In summary, hormones are essential in the menstrual cycle as they control the growth and release of eggs from the ovaries, and prepare the uterus for potential pregnancy. Any imbalance in these hormones can disrupt the cycle and affect a woman's fertility.