The Role of Hormones in the Menstrual Cycle
A woman’s body is designed to perform something that is nothing short of miraculous—the creation of life.
At the core of the female reproductive system is the menstrual cycle, two to seven days of menstruating (bleeding) every 28 days or so.
The hormones are continuously working to support bodily functions, including the regulation of the menstrual cycle. When you understand which hormones are involved in the menstrual cycle, their purpose, and how they work together, you can more easily identify menstruation-related problems.
Hormones Involved in the Menstrual Cycle
Hormone production is a function of glands in the body’s endocrine system. by glands, which create and secrete hormones to transfer chemical messages throughout blood, tissues, and organs to tell the body what to do and when to do it. Hormones regulate a wide variety of processes in the body, including growth, development, metabolism, sexual function, mood, reproduction, and more.
In the female reproductive system, several different hormones work together to create the menstrual cycle that a woman goes through each month to prepare the body for pregnancy.
These hormones include:
Gonadotropin-releasing Hormone (GnRH)
Produced in the brain's hypothalamus, GnRH travels to the pituitary gland via the bloodstream and binds to receptors that signal the gland to make other hormones that play critical roles in the menstrual cycle—FSH and LH.
Follicle Stimulating Hormone (FSH)
FSH does its work during the time when you might still be bleeding. The pituitary gland releases FSH to stimulate the follicles in your ovaries to mature.
Luteinizing Hormone (LH)
LH is one of the hormones released by the pituitary gland after the gland receives a signal from GnRH. LH is responsible for causing the dominant follicle to release an egg from the ovary during ovulation.
Estrogen is one of the major sex hormones in a woman's body. It regulates many things, but it’s primarily involved with the endometrium (lining of the uterus) during the menstrual cycle. At the beginning of a cycle, estrogen levels are low, but they continue to rise and send messages for the uterus to grow a new lining to replace the one that was shed in the previous menstrual cycle.
The other major sex hormone a woman's body produces is progesterone, which the ovaries produce after ovulation. The ovaries release progesterone after receiving a signal from the hypothalamus. Progesterone does its job near the end of the menstrual cycle. If a woman's egg is not fertilized by sperm, progesterone signals the body to start a new cycle and begin bleeding. When fertilization does occur, progesterone stimulates glands responsible for providing nutrition to the embryo.
Although testosterone is a male hormone, women's ovaries also produce testosterone. Its primary function in the female body is to regulate sex drive and overall regulation of the menstrual cycle, but it also helps to preserve muscle mass in women.
How Hormones Work Together
The menstrual cycle has three distinct phases in which your hormones work together to regulate specific aspects of the cycle. In the follicular period, which occurs before the release of the egg, estrogen and progesterone levels are low, causing the endometrium to break down, which results in bleeding. Once bleeding begins, the FSH levels increase to promote follicle development. As one follicle continues to mature, it releases more estrogen into the body.
During the next phase of the menstrual cycle, ovulation, LH and FSH levels increase, which promotes ovulation, the specific time when the follicle releases an egg. During ovulation, estrogen levels decrease in a woman's body, and progesterone levels begin to rise. Once ovulation has occurred, the luteal phase of the menstrual cycle begins.
During the third and final stage of the menstrual cycle, LH and FSH levels decrease, and the mass of cells left where the follicle ruptured and released the egg produces progesterone. In the background, estrogen levels remain high, and together with progesterone, promote the thickening of the endometrium, which will shed and start the cycle again if fertilization does not occur.
Hormone Imbalance in the Menstrual Cycle
Each hormone in the menstrual cycle plays a critical role. When even one hormone level is off, your menstrual cycle is impacted.
Irregular periods can be a sign of a hormone imbalance. The period may be light, heavy or skip its usual schedule. Acne, thinning hair, too much hair, and skin tags are physical signs of a potential hormonal imbalance.
Chronic health conditions that impact the menstrual cycle include diabetes, thyroid issues, eating disorders, stress and tumors.
Polycystic ovary syndrome (PCOS) is one of the most common examples of hormone imbalance that impacts the menstrual cycle. Scientists haven't been able to pin down an exact cause of PCOS, but they agree on one crucial factor that most likely plays a role.
Women who suffer from PCOS have high levels of male hormones, called androgens. Testosterone is the most common androgen. Women produce small amounts of testosterone in their bodies, but those with PCOS have more male hormones than usual.
High androgen levels can prevent ovulation during the menstrual cycle. Without ovulation, follicles don't rupture and start to produce progesterone, causing the entire menstrual cycle to break down.
Hormones play a crucial role in women's bodies by regulating the menstrual cycle. If you have been experiencing irregularities in your cycle, your hormones may be the cause. It's imperative that you speak with a medical professional, such as a gynecologist.
Contact West Suburban Medical Center to connect with a network of experienced doctors, surgeons, and nurses ready to help you with any women's healthcare issues, including those involving hormone imbalances.