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Estrogen - An Overview

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Estrogen is the hormone that plays a role in women's sexual and reproductive development. Read about the functions of estrogen and its importance.

Medically reviewed by

Dr. Shaikh Sadaf

Published At March 10, 2023
Reviewed AtJanuary 4, 2024

What Is Estrogen?

Estrogen (also known as sex hormone) is a group of steroid hormones responsible for developing female sexual characteristics. The ovaries, adrenal glands, and fat tissues produce estrogen hormones.

Estrogen plays a vital role in-

  • Cognitive health.

  • Bone health.

  • Cardiovascular functioning.

  • Female sexual and reproductive health.

What Are the Different Types of Estrogen?

Types of estrogen are as follows-

  1. Estrone- This is a type of estrogen mostly present in postmenopausal women. The body can easily convert it to other types of estrogen hormones if needed.

  2. Estradiol- This estrogen hormone is produced in both males and females. In females, it is responsible for developing sexual characteristics during reproductive years. Excessive estradiol production can cause acne, osteoporosis, loss of sex drive, or depression. Very high levels increase the risk of uterine or breast cancer. Low levels of estradiol can cause weight gain and cardiovascular diseases.

  3. Estriol- This type of estrogen hormone rises explicitly during pregnancy. Levels peak before delivery. Its function is to help the uterus grow and prepare the body to deliver a baby.

What Are the Functions of Estrogen?

Estrogen hormones are responsible for the following functions-

  • Vagina: It maintains the thickness of the vaginal wall and promotes lubrication.

  • Ovaries: It helps to stimulate the growth of the egg follicle.

  • Uterus: It maintains the uterine lining and regulates the flow and thickness of uterine mucus secretions.

  • Breasts: Formation of breast tissue and stopping milk flow after weaning from breastfeeding.

What Are the Factors That Affect Estrogen Levels?

Estrogen levels differ from person to person. The levels of estrogens also fluctuate due to various reasons. These fluctuations cause hot flashes or mood changes in females.

Factors affecting estrogen levels are-

  • Puberty and menopause.

  • Pregnancy and breastfeeding.

  • Factors like- Obesity, overweight, or aging.

  • Anorexia nervosa (a disorder in which people are obsessed with extreme dieting).

  • Strenuous exercise or training.

  • Turner's syndrome.

  • Medications- steroids, Ampicillin, Phenothiazines, Tetracyclines, or estrogen-containing drugs.

  • Comorbidities- high blood pressure or diabetes.

  • Polycystic ovary syndrome (PCOS).

  • Ovarian insufficiency.

  • Ovarian or adrenal glands tumors.

  • Malfunctioning pituitary gland.

What Is an Estrogen Imbalance?

An imbalance in estrogen production can lead to various problems in males and females. In females, estrogen imbalance usually occurs during menopause.

The commonly seen effects of estrogen imbalance include-

  • Heavy bleeding during menstruation.

  • Severe premenstrual or menopausal symptoms.

  • No, irregular or light menstruation.

  • Hot flashes, fatigue, and night sweats.

  • Mood swings, depression, anxiety, or sleeping disorders.

  • Abnormal weight gain (especially in hips, waist, and thigh region).

  • Low libido (sexual desire).

  • Benign lumps in breast and uterus.

  • Vaginal dryness.

  • Vaginal atrophy.

  • Dry skin.

Sometimes, males can get estrogen imbalance. Low estrogen levels can cause excess fat in the belly region or low libido in males. High levels of estrogen can be due to hereditary or other conditions, which may lead to-

  • Infertility.

  • Erectile dysfunction.

  • Gynecomastia (large breasts).

How do Estrogen Hormones Affect Women's Emotions?

Estrogen hormones are linked to a woman's emotional well-being. Estrogens are linked to various mood disruptions that occur only in women.

They are described as follows-

  • Effects on Brain - Increases serotonin production in the brain, protects nerves from damage, stimulates nerve growth, and modifies production and the effects of endorphins (the feel-good chemicals in the brain).

  • Premenstrual Syndrome (PMS) - It is the unpleasant symptoms experienced by women before their periods. These symptoms go away after the completion of the period. Symptoms can be Bloating, swelling of limbs, breast tenderness, feeling emotional, depression, anger, irritability, anxiety, or social withdrawal.

  • Premenstrual Dysphoric Disorder (PMDD) - Premenstrual dysphoric disorder is considered a severe form of premenstrual syndrome (PMS). The symptoms and emotional disturbances are severe enough to cause problems with daily life.

  • Postpartum Depression - Having depression within the first six months after childbirth is common. It occurs due to the abrupt drop in estrogen levels after delivery.

  • Perimenopausal Depression - The estrogen levels are erratic and unpredictable in the months or years before menopause. These varying estrogen levels may cause depression in perimenopausal women.

  • Postmenopausal Depression - At menopause, the estrogen levels fall, causing depression in women.

What Is Estrogen Hormone Therapy?

Low levels of estrogen hormones are responsible for various problems like symptoms due to menopause, osteoporosis, hypoestrogenism, and breast and prostate cancers. Estrogen can also be used for the prevention of pregnancy. Thus estrogen hormone therapy can be given in combinations as estrogen-only medication or estrogen and hormone combination medication.

The available estrogen preparations are as follows-

  • Oral- Oral estrogens can be prescribed as conjugated Estrogen tablets, Estradiol tablets, or Norethindrone or Ethinyl estradiol tablets (for oral contraception).

  • Vaginal Ring- An Estradiol-only vaginal ring (for vulvovaginal atrophy) or a combination Estrogen-Etonogestrel or Ethinyl Estradiol hormone vaginal ring (for contraception).

  • Intramuscular injection-

    • Estradiol valerate intramuscular injections are injected to manage menopausal symptoms, vulvovaginal atrophy, and hypoestrogenism.

    • Estradiol cypionate intramuscular injection to treat moderate to severe menopausal symptoms.

    • As a palliative treatment for advanced prostate cancer.

  • Transdermal- Topical spray, vaginal cream, vaginal tablet insert, and transdermal patch.

What Are the Side Effects of Estrogen Hormone Therapy?

Both natural and synthetic estrogen can cause some side effects like-

  • Tender breasts.

  • Nausea and vomiting.

  • Bloating.

  • Stomach cramps.

  • Headaches.

  • Weight gain.

  • Hyperpigmentation of the skin.

  • Hair loss.

  • Vaginal itching.

  • Abnormal uterine bleeding.

  • Anaphylaxis.

More severe side effects like-

  • Hypertension.

  • Cerebrovascular accident.

  • Myocardial infarction.

  • Venous thromboembolism.

  • Pulmonary embolism.

  • Epilepsy.

  • Asthma.

  • Nipple discharge.

  • Hypocalcemia.

  • Gallbladder disease.

  • Hepatic hemangioma and adenoma.

  • Pancreatitis.

  • Breast hypertrophy.

  • Endometrial hyperplasia.

  • Vaginitis.

  • Vulvovaginal candidiasis.

  • Uterine fibroids enlargement.

  • Risk of cervical cancer and breast cancer.

What Are the Contraindications for Estrogen?

Following are the contraindications for natural and synthetic estrogen-

  • Breast cancer, ovarian cancer, and endometrial cancers.

  • Thromboembolism or thrombophlebitis.

  • Coronary arterial disease.

  • Ischemic stroke.

  • Migraine headache or seizures.

  • Uterine leiomyomas, urinary incontinence, or endometriosis.

  • Dementia or neurocognitive disorders.

  • Hypertension.

  • Diseases of gallbladder or liver.

  • Hyperlipidemia.

  • Tobacco usage.


Estrogen groups of hormones play an essential role in the female reproductive system and many other body functions. Regardless of all the known risks associated with its consumption, it is still a necessary component of the oral contraceptive pill to treat postmenopausal symptoms. Estrogen hormone therapy must always be in conjunction with proper patient counseling and monitoring to maximize therapeutic effectiveness and minimize adverse effects.

Dr. Shaikh Sadaf
Dr. Shaikh Sadaf



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