hormonal changes and cycles of a woman

Hormonal Changes Throughout a Woman’s Life

Hormones

Hormones are chemical messengers in the body responsible for several important processes, including growth and development, metabolism, sexual function, and reproduction. Female sex hormones, in particular, play a vital role in women’s lives and change throughout their lifespan, particularly during puberty, pregnancy, breastfeeding, and menopause. Understanding hormonal changes throughout life as a woman can help one maneuver these changes gracefully.

Understanding the role of female hormones is important to recognize hormonal imbalances that can affect regular bodily functions. In this article, we will discuss the various hormones that affect women’s health across their lives, female hormone disorders and imbalances, and lifestyle factors that contribute to hormone health.

Types of Female Hormones

  • Estrogen

It is a hormone mainly made in the ovaries and plays a vital role in female sexual and reproductive development. It is responsible for several functions, including stimulating the growth of the egg follicle in the ovaries, maintaining the thickness of the vaginal wall, promoting lubrication in the vagina, maintaining the mucous membranes lining the uterus, and forming the breast tissue.

Estrogen is also responsible for developing secondary sexual characteristics, including pubic hair and armpit hair. Furthermore, it is also responsible for maintaining other parts of the body, including the cardiovascular and musculoskeletal systems, brain, bones, and hair.

  • Progesterone

It is a hormone released by the ovaries, particularly the corpus luteum in the ovary. It is also released by the adrenal glands and placenta. Raised progesterone levels are responsible for preparing the body for pregnancy if fertilization of the egg occurs. Low levels of progesterone in the absence of fertilization cause menstruation.

  • Testosterone

Testosterone is one of the main hormones of males. However, it is also present in females and affects menstruation, sexual desire, fertility, red blood cell production, and tissue and bone mass.

  • Follicle-Stimulating Hormone (FSH)

It is responsible for the maturation of the follicles in the ovaries. It also plays a role in puberty.

  • Luteinizing hormone (LH)

It is an important hormone during the menstrual cycle and causes the egg to be released from the ovary through a process known as ovulation.

Hormone changes during puberty

Puberty usually occurs between 8-13 years. During puberty, the FSH and LH levels increase, stimulating the production of the sex hormones (estrogen, progesterone, and testosterone). Raised levels of the sex hormones, mainly estrogen, cause the maturation of the breasts, ovaries, vagina, and uterus.

During puberty, females experience thelarche (beginning of breast development) with the formation of breast buds that mature over two years mediated by estrogen and progesterone. Females also experience the development of secondary sexual characteristics, including pubic hair and armpit hair, during puberty, which is mediated by testosterone. Females also undergo their first menstrual cycle during puberty, which involves several hormonal changes.

Hormone changes during menstruation

Menarche is the first menstrual cycle in females and can occur between 8-15 years. Menstrual cycles are usually for 28 days until menopause. Several hormonal changes occur that varies depending on the phase of the menstrual cycle:

  • Follicular phase

The follicular phase begins on the first day of your period and ends during ovulation. During this phase, the pituitary gland receives a signal from the hypothalamus to release the follicle-stimulating hormone (FSH). This hormone causes your ovaries to release 5-20 follicles, each containing an immature egg. Only one egg matures (sometimes two), and the rest are reabsorbed by the body.

As the egg matures, estrogen levels rise, which causes the uterus lining to thicken to prepare for a potential pregnancy.

Increased testosterone levels can suppress the ovulation phase and cause few or no menstrual periods.

  • Ovulation phase

The rising estrogen levels during the follicular phase cause your hypothalamus to recognize these levels, which releases the gonadotrophin-releasing hormone (GnRH). This hormone prompts your pituitary gland to release the luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

The high levels of LH trigger ovulation within two days. During this phase, the mature egg is released from the surface of the ovary and travels down the fallopian tube towards the uterus. The egg lasts for 24 hours. If it is met by a sperm, pregnancy occurs; otherwise, it dies. The ovulation phase occurs mid-way through the menstruation cycle.

At this phase, elevated testosterone levels are also present, which increases libido.

  • Luteal phase

The luteal phase begins after ovulation and ends on the first day of your period. During this phase, the ruptured follicle that released the mature egg during the ovulation phase changes into a structure known as the corpus luteum. This structure releases progesterone and a small amount of estrogen. These hormones thicken the lining of the uterus to implant a fertilized egg.

If a fertilized egg implants in the uterine lining, it produces the hormones needed to maintain the corpus luteum, including human chorionic gonadotrophin (HCG) hormone, which is used to detect pregnancy in urine tests. It stimulates the corpus luteum to continue producing the high levels of progesterone required to maintain the thick uterus lining.

If fertilization does not occur during ovulation, the corpus luteum withers away and dissolves in the body. Progesterone and estrogen levels then drop, which causes the uterus lining to fall away, causing menstruation or a period.

Hormone changes during pregnancy

The ovaries and later the placenta is mainly responsible for releasing hormones during pregnancy. The hormones help create an environment for the pregnancy to be successful. When the egg implants in the uterus, it releases the HCG hormone, responsible for maintaining raised progesterone and estrogen levels to maintain the pregnancy.

Progesterone serves several critical roles during early pregnancy, including increasing blood flow to the womb, stimulating the uterine lining glands to produce nutrients for the embryo, stimulating the uterine lining to thicken, and helping grow the placenta.

Development of the placenta causes it to produce hormones as well. The placenta’s cells (trophoblasts) convert cholesterol in the mother’s bloodstream into progesterone, which then becomes the main source of progesterone.

Apart from early pregnancy, progesterone is also responsible for several functions during mid and late pregnancy. It helps ensure the correct development of the fetus, prevents the womb’s muscles from contracting until labor, strengthens the pelvic muscles walls for labor, and prevents lactation until pregnancy.

Estrogen helps stimulate progesterone production from the placenta. The corpus luteum of the ovaries is initially responsible for estrogen production, and production is later taken over by the fetal-placental unit. The fetal liver and adrenal glands produce estriol, a type of estrogen that determines fetal wellbeing. Estrogen affects several functions, including stimulating and maintaining other pregnancy hormones, stimulating the placenta’s growth and functions, ensuring correct development of fetal organs, encouraging maternal breast tissue growth, and preparing the mother for lactation.

The placenta also releases human placental lactogen during pregnancy (hPl), which helps provide nutrition to the fetus.

Hormone changes during breastfeeding

The hormones prolactin and oxytocin directly affect breastfeeding. However, other hormones, including estrogen, are indirectly involved. Breastfeeding affects the pituitary hormones (GnRH, FSH, and LH), which help suppress ovulation and menstruation to delay a new pregnancy.

  • Prolactin

Prolactin levels increase during pregnancy and encourage the growth of mammary tissues in preparation for milk production. During pregnancy, milk is not secreted because progesterone and estrogen block prolactin from inducing lactation. Since progesterone and estrogen levels fall after pregnancy, prolactin is no longer blocked, thus allowing milk secretion.

  • Oxytocin

Oxytocin is responsible for the “milk-ejection reflex.” This reflex becomes conditioned to the mother’s feelings and sensations. It helps produce the milk when the baby is suckling or when the mother suspects a feed.

Oxytocin levels also rise during labor and birth. It helps progress labor by contracting the uterus. It also helps reduce stress and anxiety during labor.

Hormone changes during perimenopause

Perimenopause occurs between mid-thirties to early fifties. It is when the body transitions to menopause and can last for years. Estrogen and progesterone levels drop or fluctuate during this period, causing the menstrual cycle to become irregular or erratic.

FSH levels also fluctuate during perimenopause. When FSH levels drop, estrogen also drops, and when it is high, estrogen levels also increase.

Hormone changes during menopause

Menopause typically occurs between mid-forties to mid-fifties. During menopause, menstruation stops completely, and ovulation does not occur, resulting in low levels of progesterone and estrogen production.

The lack of estrogen can cause hot flashes and night sweats, which occur for a few years following menopause. Moreover, lower estrogen levels also cause incontinence or a lack of voluntary control over urination. This often causes bladder leakage when you laugh or sneeze. After menopause, the body only produces estrone, a type of estrogen.

Other symptoms people can experience after menopause include weight gain, hair loss, vaginal dryness, dry skin, depression, and change in sex drive.

Testosterone levels are at half their peak when the body reaches menopause, compared to their levels when a woman is in her twenties.

What causes hormonal imbalance in females

Hormone imbalance occurs when the hormones are outside their normal range in the bloodstream. Hormones usually fluctuate during menstruation, ovulation, pregnancy, and menopause; however, sometimes fluctuations can be due to an underlying medical condition, medications, or lifestyle habits.

These fluctuations can cause

  • Bloating
  • Weight gain
  • Hair loss
  • Mood swings
  • Infertility
  • Fatigue
  • Blood sugar problems
  • Hormonal imbalance and fertility problems

The major cause of infertility in women is hormonal imbalance. High FSH levels and low LH levels can reduce the chances of pregnancy.

  • Hormonal imbalance and heavy periods

Heavy or painful periods, along with other symptoms such as abdominal pain, lower back pain, and frequent urination, is potentially due to fibroids (non-cancerous growths in the uterus), which are suggested to be stimulated by high estrogen levels.

  • Hormone imbalance and polycystic ovarian syndrome (PCOS)

PCOS occurs when the ovaries produce excessive androgens, such as testosterone. It causes small cysts (fluid-filled sacs) to develop in the ovaries. This causes menstrual cycle problems such as irregular, missed, or very light periods. Other symptoms include excessive body hair, weight gain, hair loss, and infertility.

Factors that influence hormone health

Several factors can affect hormonal health and cause an imbalance. These include

  • Unhealthy diet
  • Having a high body fat percentage
  • Type 1 and Type 2 diabetes
  • Thyroid problems
  • Birth control medications
  • Hormonal replacement medications
  • Pollutants
  • Endocrine gland injury
  • Endocrine gland cysts
  • Steroid medication abuse
  • Radiation therapy or chemotherapy
  • Anorexia
  • Over-exercising
  • Lack of sleep
  • Stress

It’s okay to seek help when you need it.  Taking natural supplements to help maintain healthy hormone balance and get your body back on track may be just what you need.  Of course, other factors such as eating right and not using toxic products play a role in keeping your hormones balanced as well.  There isn’t one thing that contributes to hormone imbalances although one factor may contribute more than another.  Having thyroid support can also be very effective in promoting the right healthy environment for your hormones to stay balanced.  Finally, be sure to sustain your adrenal health especially when you are stressed. 

Hormonal Changes Throughout a Woman\'s Life

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