Female Reproductive Hormones 101: What Are Hormones?

Knowing how your reproductive system works is a powerful part of taking charge of your health. This quick guide breaks down the female hormones that support fertility, menstruation, and overall well-being.

Key Takeaways:

• Four key hormones—estrogen, progesterone, FSH (Follicle-Stimulating Hormone), and LH (luteinizing hormone)—work together to guide the menstrual cycle and support your body through each phase.
• The menstrual cycle happens every month when hormone levels naturally rise and fall throughout the month, keeping your periods regular, supporting ovulation, and influencing how you feel day to day.
• Changes in these hormones can influence mood, energy, and physical sensations, and it’s normal for these experiences to vary from person to person.
• Hormonal contraception regulates the changes in hormone levels in predictable ways, and work by preventing ovulation or thickening cervical mucus.
• Understanding your hormones helps you better understand your body’s signals and make choices that fit your health, comfort, and lifestyle.

What are the main female reproductive hormones and their function?

Reproductive hormones are chemical messengers produced by the brain and ovaries. They regulate the phases of the menstrual cycle, and play roles throughout our lives. The main female reproductive hormones are estrogen and progesterone, with supporting hormones including testosterone, LH, and FSH.

What is Estrogen?

Estrogen is mainly produced in the ovaries, and plays key roles in helping your body grow, prepare, and maintain key reproductive tissues.

Kinds of Estrogen

1. Estradiol (E2):
The main estrogen your body makes during your reproductive years. It’s the form that does most of the everyday work; from supporting your menstrual cycle to helping with bone, brain, and metabolic health.

2. Estrone (E1):
The form of estrogen your body shifts toward after menopause. It’s still active, but not as strong as estradiol.

3. Estriol (E3):
A weaker form of estrogen; levels rise during pregnancy to help support the body as it rapidly changes.

Estrogen also:

• Rebuilds the uterine lining after your period, getting the body ready for a possible pregnancy.
• Supports follicle growth in the ovary, helping eggs mature for ovulation.
• Changes cervical mucus so it’s stretchy and fluid, creating the right environment for fertilization.
• Drives puberty changes, like breast development and hip widening.
• Maintains tissues like bones, skin, and vaginal health throughout life.

In simple terms: Estrogen helps build and prepare the body for reproductive health and overall wellness.

What is Progesterone?

Progesterone is a hormone that supports menstruation and helps maintain early pregnancy. The levels of progesterone rise in the body after ovulation. Its main job is to prepare the lining of the uterus (endometrium) for pregnancy. If pregnancy doesn’t occur, progesterone levels drop, which signals to the body to start a new menstrual cycle.

Progesterone also:

• Thickens the uterine lining to support a fertilized egg.
• Supports pregnancy by preventing ovulation during pregnancy and suppressing uterine contractions.
• Helps breasts prepare for breastfeeding and supports lactation.
• Influences common menstrual experiences, like bloating, breast tenderness, or mood changes.

In simple terms: Progesterone is a “stabilizer” for the second half of the menstrual cycle.

What is Testosterone?

Testosterone is an androgenic hormone produced in small but essential amounts in women. Testosterone and other androgens play an important role in reproductive health and supporting normal ovulation. These hormones are also used by the body to make estrogen. Small amounts of androgens help follicles, the sacs that hold eggs, grow and mature properly. Unusually high levels of androgens, like in polycystic ovary syndrome (PCOS), can cause many small fluid-filled follicles (cysts) to start developing. These follicles don’t regularly release eggs and then get “stuck,” which can lead to irregular periods and reduced fertility.

In simple terms: Testosterone helps support healthy egg development, hormone balance, and contributes to sexual and overall wellness.

What is Luteinizing hormone (LH)?

LH is a hormone made by the pituitary gland and plays a key role in the menstrual cycle. Think of it as the “trigger” for ovulation.

Here’s what it does:

• Triggers ovulation: A sharp rise in LH (called the LH surge) signals the ovary to release a mature egg.
• Supports the corpus luteum: After ovulation, LH helps the corpus luteum form and then produce progesterone to prepare the uterus for a potential pregnancy.
• Works with estrogen: LH and estrogen communicate to time ovulation and keep the cycle running smoothly.

In simple terms: LH is the hormone that tells your ovary, “Time to release the egg!” and helps set up your body for the next stage of the cycle.

What is Follicle-stimulating hormone (FSH)?

FSH is a hormone made by the pituitary gland that acts like a “starter signal” for a follicle in one of the ovaries to begin maturing early in the menstrual cycle.

Here’s what it does:

• Kick-starts follicle growth: FSH tells several ovarian follicles (the tiny sacs that hold eggs) to begin growing each cycle.
• Helps one follicle become dominant: Usually, one follicle takes the lead and matures into a fully mature egg that will be released.
• Prepares for ovulation and pregnancy: the dominant follicle produces estrogen which suppresses FSH. After ovulation, the ruptured follicle produces progesterone which blocks the release of FSH and helps prepare the uterus lining for pregnancy.

In simple terms: FSH is the hormone that tells your ovaries, “Get ready — time to grow some eggs!”

What is Gonadotropin-Releasing Hormone (GnRH)?

GnRH is a hormone made by the hypothalamus in your brain. Think of it as the “boss hormone” that tells other hormones what to do.

Here’s what it does:

• Signals the pituitary gland: GnRH tells the pituitary to release FSH and LH, the hormones that control egg growth and ovulation.
• Controls the menstrual cycle: By regulating FSH and LH, GnRH keeps your cycle on track from one phase to the next.

In simple terms: GnRH is the hormone that sets the whole reproductive hormone system in motion, making sure your ovaries and cycle work properly.

Other Reproductive Hormones

Other hormones also support the female reproductive system:

Anti-Müllerian hormone (AMH)

is made by the small growing follicles in the ovaries and helps regulate how many eggs begin to mature each cycle. AMH levels are used to estimate how many eggs you have left.

Relaxin

is a hormone mainly produced in the ovaries. During pregnancy, it’s also made by the placenta and uterine tissues. It helps your body prepare for pregnancy by relaxing the uterine muscles to support implantation, and later it helps soften and loosen pelvic tissues so the body can comfortably adapt as pregnancy progresses and prepares for childbirth.

Female Reproductive Hormones and their function

Estrogen

• Drives puberty and secondary sex characteristics.
• Regulates the menstrual cycle.
• Helps trigger ovulation.
• Thickens the uterine lining to prepare for potential pregnancy.
• Decreases during menopause.

Progesterone

• Thickens the uterine lining after ovulation.
• Supports early pregnancy and prevents uterine contractions.
• Drops to trigger menstruation when no pregnancy occurs.

Testosterone

• Supports libido (sex drive).
• Supports bone and muscle health.
• Influences mood and energy.

Luteinizing hormone (LH)

• Supports estrogen production early in the cycle.
• Triggers ovulation in an event called the LH surge.
• Supports progesterone production after ovulation.

Follicle-stimulating hormone (FSH)

• Stimulates growth and maturation of ovarian follicles (eggs).
• Promotes estrogen production by follicles.

Gonadotropin-releasing hormone (GnRH)

• Signals the pituitary gland to release LH and FSH.

Anti-Müllerian hormone

• Regulates how many follicles begin maturing each cycle.
• Levels reflect the number of remaining follicles (ovarian reserve).

Relaxin

• Softens the uterus and surrounding tissues to prepare for pregnancy.

Common hormone disorders in women

Hormones help keep your body and reproductive system running smoothly. Some common conditions caused by hormonal imbalances or disorders include:

Polycystic Ovary Syndrome (PCOS)

While the cause of PCOS is not well understood, women with PCOS have higher amounts of androgens. This hormone imbalance can cause a number of health problems related to the reproductive system like preventing ovulation and affecting fertility, according to ACOG.

Female Infertility

In addition to PCOS, there are other hormone imbalances that can cause ovulation disorders. Hypothalamic dysfunction — a disruption in the production of FSH and LH — can be caused by too much physical or emotional stress or big changes in body weight and disrupt periods. Another example is a condition where the pituitary gland causes production of too much prolactin (hyperprolactinemia) which reduces estrogen and can cause infertility.

Premenstrual Syndrome (PMS) and Premenstrual Dysphoric Disorder (PMDD)

Sensitivity to the normal fluctuations in estrogen and progesterone can trigger significant mood changes and physical symptoms before your period.

What other hormones could impact reproductive health?

Thyroid hormone

Regulates your body’s metabolism. Hypothyroidism (underactive thyroid), hyperthyroidism (overactive thyroid), and other thyroid issues can affect your reproductive hormones and menstrual cycle and fertility.

Prolactin

High levels can make it harder to get pregnant by interfering with ovulation.

Androgens (like testosterone)

Increased levels of androgens may contribute to PCOS.

Cortisol

Plays a key role in managing your body’s response to stress. Chronically elevated cortisol from stress can affect hormone signaling, potentially impacting your cycle.

Insulin

High insulin levels can influence ovarian function and increase risk for PCOS.

Causes and symptoms of hormonal imbalances

Hormonal imbalance can come from a variety of factors — from stress and diet to gland problems or life stages — that disrupt the delicate chemical messaging system in your body.

Common Causes of Hormonal Imbalance

Hormonal imbalance can come from a variety of factors — from stress and diet to gland problems or life stages — that disrupt the delicate chemical messaging system in your body.

Gland problems

thyroid, pituitary, adrenal glands, ovaries

Stress & lifestyle

chronic stress, poor sleep, extreme or insufficient exercise

Nutrition & weight

obesity, malnutrition, micronutrient deficiencies

Medications & substances

steroids, hormonal contraceptives (which intentionally modify hormone levels), alcohol, certain drugs

Genetic/autoimmune conditions

Aging

perimenopause or menopause

Certain conditions, like polycystic ovary syndrome (PCOS) or Turner syndrome, can also lead to hormone imbalances.

Common symptoms of reproductive hormone imbalance

generally include:

1. Irregular periods
2. Acne
3. Low sex drive
4. Heavy periods
5. Hair loss
6. Excess body or facial hair (hirsutism)
7. Vaginal dryness
8. Hot flashes
9. Infertility

While it isn’t considered a hormonal imbalance, hormonal birth control works by providing controlled levels of synthetic hormones that adjust the body’s natural cycle which prevents pregnancy and may lead to changes in your period.

How to Support Hormonal and Overall Health⁸

It’s important to know that hormone disorders can affect anyone — even if you eat well and exercise regularly. Genetics, medical conditions, stress, life stages, and other factors can all influence hormone balance, however there are some habits that help support overall well-being and reproductive health.

Diet and Nutrition

Food can play a supportive role in hormone and reproductive health.

• Eat plenty of fresh fruits, vegetables, and whole grains.
• Include low- or non-fat dairy, seafood, legumes, and nuts.
• Limit red and processed meats.
• Limit processed foods, added sugars, alcohol, and caffeine.
• Stay hydrated to help your body function optimally.

Active Lifestyle and Exercise

Regular exercise has both physical and emotional benefits and can help to reduce stress, support metabolism and weight management, build bones and muscles, and contribute to overall well-being and reproductive health.

• Aim for at least 150 minutes of moderate to vigorous physical activity each week, like walking, cycling, or strength training.
• Making small changes, like taking the stairs or parking further away, can contribute to an active lifestyle.
• Limit sedentary time by breaking up long periods of sitting as often as possible.

Stress Management

Managing stress helps keep your menstrual cycle and reproductive hormones on track.

• Practice stress-reducing activities such as meditation, yoga, or deep breathing.
• Journaling, hobbies, and time in nature can also help lower stress.

Sleep

Good sleep supports hormone regulation, energy levels, and overall health.

• Aim for 7 to 9 hours of good-quality sleep each night.
• Try to keep a consistent sleep schedule to maintain your body’s natural rhythm.

What Every Woman Should Know About Hormonal Health

Your reproductive hormones do more than drive your cycle — they can also influence your energy, mood, and overall health. Understanding the basics of how female reproductive hormones estrogen, progesterone, FSH, and LH work together can help you have more informed conversations with your healthcare provider to guide your personal choices about contraception, fertility, and wellness.

For more, science-backed insights on birth control, cycles, hormones, and women’s health, we welcome you to explore more of our blog.

 

LEARN MORE

 

[1] Medical News Today. What to know about female sex hormones. November 2024. https://www.medicalnewstoday.com/articles/324887. Accessed February 2026.

[2] Endocrine Society. Reproductive Hormones. January 2022. https://www.endocrine.org/patient-engagement/endocrine-library/hormones-and-endocrine-function/reproductive-hormones. Accessed February 2026.

[3] Cleveland Clinic. Female Reproductive System. November 2022. https://my.clevelandclinic.org/health/articles/9118-female-reproductive-system. Accessed February 2026.

[4] Johns Hopkins Medicine. Thyroid Disorders in Women; Johns Hopkins Medicine Health. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/thyroid-disorders-in-women. Accessed February 2026.

[5] Cleveland Clinic. Thyroid Hormone. February 2022. https://my.clevelandclinic.org/health/articles/22391-thyroid-hormone. Accessed February 2026.

[6] American College of Obstetricians and Gynecologists. Polycystic Ovary Syndrome (PCOS). April 2025. https://www.acog.org/womens-health/faqs/polycystic-ovary-syndrome-pcos. Accessed February 2026.

[7] Centre for Disease Control. Physical Activity Basics. Adult Activity: An Overview. December 2023. https://www.cdc.gov/physical-activity-basics/guidelines/adults.html. Accessed February 2026.

[8] Office on Women’s Health. Sleep and your health. May 2025. https://womenshealth.gov/mental-health/good-mental-health/sleep-and-your-health. Accessed February 2026.

[9] Nutrition Working Group, et al. Canadian Consensus on Female Nutrition: Adolescence, Reproduction, Menopause, and Beyond. Journal of Obstetrics and Gynaecology Canada. 2016;38(6):508-554.