Estrogen and Progesterone in Females

And What Imbalanced Levels Could Signal

Medically reviewed by Do-Eun Lee, MD

Estrogen and progesterone are the primary reproductive hormones in people assigned female at birth. These hormones drive puberty, menstrual cycles, and pregnancy. They are also present in those assigned male at birth but to a lesser degree. Estrogen and progesterone imbalances can cause menstrual cycle disruptions, mood changes, hot flashes, and infertility. They can also have an impact on hormone receptor-positive (HR-positive or HR+) cancers.

This article reviews the differences between estrogen and progesterone, related conditions, the effects of low and high levels, hormone therapy, and ways to balance hormones naturally.

Biologically, What Do Estrogen and Progesterone Do?

While estrogen and progesterone are the primary sexual, or reproductive, hormones in people assigned female at birth, they also play a role in the male reproductive system. Estrogen influences the development of female reproductive organs and is responsible for sexual characteristic development during puberty, such as breast growth and hip widening.

Estrogen and progesterone are responsible for the following in females:

• Puberty

• Pregnancy

• Breastfeeding

• Menstrual cycles

• Menopause

• Mood

• Sex drive

• Bone health

Types of Estrogen (Estradiol, Estrone, Estriol)

Estrogen encompasses a group of hormones, including:

• Estradiol: The most prominent type of estrogen present in the body before menopause, estradiol helps mature and maintain the female reproductive system. The ovaries produce estradiol.

• Estrone: After menopause, estrone is the primary type of estrogen present in the body. Its production occurs in the adipose (fat) tissue.

• Estriol: Made by the placenta, estriol is present in the body during pregnancy.

Estrogen's Role

Estrogen has the following benefits:

• Initiates the menstrual cycle

• Promotes a healthy libido (sex drive)

• Protects reproductive, cardiovascular (heart and blood vessels), bone, and skin health

• Supports metabolism

• Helps maintain healthy cholesterol levels

• Mood regulation

• Promotes cognitive function (mental sharpness)

In males, estrogen regulates bone density, sperm production, and libido (sex drive). Progesterone aids in producing testosterone (the primary male reproductive hormone).

Progesterone's Role

Progesterone production primarily occurs in the corpus luteum, a natural, temporary cyst-like structure that develops on an ovary each menstrual cycle. In females, the following are the main functions of progesterone:

• Thickens the uterine lining, preparing it for possible implantation

• Maintains pregnancy by keeping the uterus from contracting

• Prepares the breasts for lactation to support breastfeeding

• Balances estrogen

Conditions and Effects of Low Estrogen and Progesterone

Low estrogen or progesterone levels (or both) can occur due to menopause, health conditions, excessive exercise or calorie restriction, an unhealthy diet, or medical treatments.

During perimenopause, the time leading up to menopause, estrogen and progesterone levels fluctuate. Levels of both hormones decrease during menopause.

In addition to perimenopause and menopause, hormonal imbalances may occur in the following conditions or situations:

• Insulin resistance

• Obesity (causes insulin resistance)

• Stress

• Unhealthy or imbalanced gut microflora (good and bad bacteria)

• Damage to or surgical removal of the ovaries (which induces surgical menopause)

• Excessive exercise, extreme calorie restriction, or rapid weight loss

• Endocrine conditions (thyroid or pituitary gland disorders)

• Genetic conditions, including Turner syndrome

• Autoimmune conditions

• Premature ovarian failure (POF), when the ovaries stop functioning before the age of 40

• Polycystic ovary syndrome (PCOS)

• Specific cancer treatments, such as chemotherapy or radiation

• Chronic kidney disease

Conditions and Effects of High Estrogen and Progesterone

Estrogen dominance is a hormonal imbalance in which there is an excess of estrogen relative to other hormones, such as progesterone. It can occur due to the overproduction of estrogen or a change in how the body processes and excretes estrogen.

Some health conditions associated with or worsened by estrogen dominance include:

• HR-positive breast cancer

• Uterine cancer

• Uterine fibroids

• Endometriosis

• PCOS

Hormone Receptor-Positive/Negative Cancers

HR-positive cancers have receptors that can bind with estrogen or progesterone (or both), stimulating their growth. Healthcare providers use biopsies (tumor tissue samples) to evaluate HR status, which helps guide treatment.

For example, treatment for hormone-positive cancers involves medications that block the production or effects of estrogen or progesterone. But hormone receptor-negative (HR-negative or HR-) cancers would not respond to this treatment and typically require other therapies, such as chemotherapy.

Estrogen dominance can lead to the following:

• Weight gain or bloating

• Menstrual changes (e.g., lighter or heavier bleeding, shorter or longer cycles, worsening premenstrual symptoms)

• Fibrocystic (noncancerous) breast lumps

• Uterine fibroids (noncancerous tumors in the uterus)

• Fatigue

• Headaches

• Mood changes

• Decreased sex drive

• Memory or sleeping issues

• Breast tenderness

High estrogen in males can cause:

• Enlarged breasts

• Problems with erections

• Infertility

• Loss of muscle tone

Higher progesterone levels compared to estrogen can cause:

• Delayed or skipped menstrual periods

• Mood changes

• Fatigue

Comparing Estrogen and Progesterone Hormone Therapy

Hormone replacement therapy (HRT) is a medical treatment involving synthetic estrogen, progesterone (progestin), or a combination of both to supplement or replace the body's natural hormones.

Hormonal birth control such as pills, patches, shots, intrauterine devices (IUDs), implants, or vaginal rings are similar to HRT in that they use synthetic estrogen or progesterone. However, their purpose is to prevent pregnancy and regulate the menstrual cycle.

Hormonal Birth Control or Hormone Replacement Therapy?

Healthcare providers typically prescribe hormonal birth control rather than HRT for those in perimenopause (the time leading up to the cessation of the menstrual cycle known as menopause), as females can still get pregnant during this transition. However, HRT is given to those in menopause because pregnancy prevention is no longer a concern.

Estrogen Replacement Therapy

Estrogen replacement therapy is effective for relieving menopausal symptoms, but it may increase the risk of uterine cancer when given without progesterone. Providers typically reserve it for menopausal females without a uterus. Adverse effects are higher with systemic (throughout the body) estrogen than local estrogens, such as vaginal estrogen creams.

Progesterone (Progestin) Replacement Therapy

Progesterone (progestin) replacement therapy is typically for females who:

• Still have their uterus (to protect the uterine lining from the potential increased risk of uterine cancer with estrogen)

• Are sensitive to estrogen

• Have a health condition that makes estrogen risky (e.g., certain cancers and blood clotting disorders)

Progestin may also be necessary for those with PCOS or recurrent miscarriages due to low progesterone.

Side effects of progestin may include:

• Mood changes

• Bloating or breast tenderness

• Headaches

• Breakthrough bleeding

• High blood pressure

• Low blood sugar

The link between synthetic progesterone (progestin) and weight gain is a topic of debate and ongoing research. Some studies suggest that progestin may cause weight gain, while others have not found a link.

Combined Estrogen And Progesterone

Combined estrogen and progesterone (EPT) may be the best choice for those with a uterus. Progesterone helps counteract estrogen's possible negative effect on the uterine lining, reducing the risk of endometrial cancer.

Estrogen replacement relieves menopausal symptoms such as hot flashes, night sweats, vaginal dryness, and bone loss. However, taking estrogen alone increases the risk of uterine cancer.

It usually is given as follows:

• With no uterus: Providers may prescribe estrogen-only therapy for those who do not have a uterus due to a hysterectomy.

• With a uterus: Those with a uterus should receive combined estrogen and progesterone therapy. The added progesterone helps protect the uterine lining from cancer due to estrogen therapy.

How a Provider Diagnoses Potential Hormone Imbalances

Symptom tracking may be enough for a healthcare provider to diagnose and treat sex hormone imbalances in some people. However, others may need diagnostic hormone blood tests or imaging tests.

For example, a provider may prescribe hormonal treatment without further testing if you are in your mid to late 40s with perimenopausal symptoms.

But if you are younger, are experiencing infertility, or have had recurrent miscarriages, hormone blood levels and imaging studies provide helpful information.

HRT Risks

Regardless of the type of hormone treatment, providers typically recommend the lowest dose possible over a short time to reduce the following risks, as follows: 

• Estrogen only (ET) and combined estrogen and progesterone (EPT) increase the risk of blood clots and stroke

• Estrogen increases the risk of uterine cancer for those with a uterus

• Combined HRT slightly increases the risk of breast cancer

• Risks are greater in those over age 60

• Risks of blood clots and stroke are greater for those who smoke cigarettes
  

Ways to Balance Estrogen and Progesterone Levels

A healthy lifestyle can help decrease the risk of hormone imbalance. This includes:

• Maintaining a healthy weight

• Eating a nutrient-dense diet low in sugar and processed foods

• Regular physical activity

• Maintaining gut health (consider probiotics)

• Reducing stress

• Getting plenty of sleep

• Avoiding excessive alcohol intake

• Avoiding xenoestrogens (environmental chemicals that mimic estrogen, including polychlorinated biphenyls (PCBs), bisphenol A (BPA), and phthalates) found in pesticides, plastics, and personal care products

Some experts note that an anti-inflammatory or vegetarian diet helps prevent estrogen dominance. Supplements that may also help decrease the risk of inflammation and balance hormones include:

• Omega-3 supplements

• Ginger

• Turmeric

Estrogen Boosters

If you are low in estrogen, you can include phytoestrogens which are natural estrogen boosters found in foods such as:

• Edamame

• Chickpeas

• Lentils

• Flaxseed

• Tofu

If you have HR-positive cancer, check with your healthcare team before consuming large amounts of these foods.

Some herbs and supplements such as black cohosh, evening primrose oil, red clover, maca root, and Dong Quai may help support hormone balance and help relieve perimenopausal and menopausal symptoms.

Summary

Estrogen and progesterone are the primary reproductive hormones that drive puberty, menstrual cycles, the sex drive, pregnancy, and lactation (breastfeeding) in people assigned female at birth. They also play a small role in male reproduction.

Imbalances between these hormones can cause menstrual cycle disruptions, mood changes, infertility, and impact hormone receptor-positive cancers. Hormone replacement therapy HRT and hormonal contraceptives are potential treatments for hormonal imbalances. However, they come with some risks. If you are experiencing symptoms of hormonal imbalance, talk to a healthcare provider for support and treatment options.