Hormones Involved in the Menstrual Cycle

Written by Georgia Spence BSc ANutr

The menstrual cycle is a complex combination of hormones that regulate the reproductive system, prepare the body for potential pregnancy, and maintain overall female health. Understanding these hormones and their functions can provide insights into the biological processes, and empower you to understand your body.

So let's explore the key hormones involved in the menstrual cycle:

But first please below a diagram of the female anatomy (BBC https://www.bbc.co.uk/bitesize/guides/znxnscw/revision/2)

1)Oestrogen, sometimes written by estrogen:

Oestrogen is the primary female sex hormone, produced mainly by the ovaries. It plays a crucial role in regulating the menstrual cycle and supporting reproductive health.

The Function of Oestrogen:

During the follicular phase (the first phase in the menstrual cycle) oestrogen levels rise which causes the growth of the uterine lining (endometrium) and the maturation of ovarian follicles.

During ovulation there is a increase in oestrogen levels, which triggers the release of the luteinizing hormones (LH) from the pituitary gland, leading to ovulation (the release of the mature egg from the ovary.

After ovulation, oestrogen helps to maintain the thickened uterine lining in preparation for a potential pregnancy.

If fertilization does not occur, oestrogen levels drop, causing the uterine lining to shed, resulting in menstruation.

2) Progesterone

Progesterone is another vital hormone produced by the ovaries.

Functions of Progesterone:

Progesterone prepares the endometrium for the implantation of a fertilized egg and supports early pregnancy by maintaining the uterine lining.

If pregnancy occurs, progesterone levels remain high to support the developing embryo and prevent further ovulation.

If there is no pregnancy, progesterone levels decrease, leading to the shedding of the uterine lining.

3. Follicle-Stimulating Hormone (FSH)

FSH is produced by the pituitary gland and is essential for the growth and maturation of ovarian follicles.

Functions of FSH:

FSH stimulates the growth of multiple follicles in the ovaries, each containing an immature egg. This hormone also promotes the production of estrogen by the follicles. Typically, one follicle becomes dominant and continues to mature, while the others regress.

4)Luteinizing Hormone (LH)

LH, is also produced by the pituitary gland and is crucial for triggering ovulation.

Functions:

A surge in LH levels, prompted by rising estrogen levels, causes the dominant follicle to release its mature egg.

After ovulation, LH supports the transformation of the ruptured follicle into the corpus luteum, which secretes progesterone.

5) Testosterone

Though often associated with male health, testosterone plays important roles in the female body as well.

Functions:

Testosterone contributes to libido, energy levels, and the maintenance of muscle and bone mass. It assists in the growth and development of ovarian follicles.

6) Cortisol

Cortisol, known as the stress hormone, can impact the menstrual cycle when levels are elevated due to chronic stress.

Functions:

High cortisol levels can disrupt the balance of reproductive hormones, potentially leading to irregular menstrual cycles.

7) Insulin

Insulin, a hormone that regulates blood sugar levels, can affect the menstrual cycle, particularly in conditions like polycystic ovary syndrome (PCOS).

Functions:

Imbalanced insulin levels can influence ovarian function and hormone production, often leading to irregular or absent menstrual cycles.

Conclusion

The menstrual cycle is a finely tuned process orchestrated by a symphony of hormones. Each hormone has a specific role in preparing the body for potential pregnancy and maintaining reproductive health. Understanding these hormones can help individuals recognize the signs of hormonal imbalances and seek appropriate care. For personalized advice and support, consider consulting a nutritionist or healthcare professional who specializes in hormonal health.