What is an estradiol test?

An estradiol test measures the amount of the hormone estradiol in your blood. It’s also called an E2 test. Estradiol is a form of the hormone estrogen. It’s also called 17 beta-estradiol. The ovaries, breasts, and adrenal glands make estradiol. During pregnancy, the placenta also makes estradiol.
Estradiol helps with the growth and development of female sex organs, including the:

• uterus
• fallopian tubes
• vagina
• breasts

Estradiol helps to control the way fat is distributed in the female body. It’s also essential for bone and joint health in females.

Males also have estradiol in their bodies. Their levels of estradiol are lower than the levels in females. In males, the adrenal glands and testes make estradiol. Estradiol has been shown in vitro to prevent the destruction of sperm cells, but its clinical importance in sexual function and development in men is likely less significant than in women.

Why do I need an estradiol test?

Your doctor may order an estradiol test if female or male sex characteristics aren’t developing at the normal rate. An estradiol level that’s higher than normal indicates that puberty is happening earlier than usual. This is a condition known as precocious puberty.

Lower levels of estradiol may indicate late puberty. The test can help your doctor find out if there are problems with your adrenal glands. It can also help determine if treatment for hypopituitarism, or decreased function of the pituitary gland, is working.

Your doctor may order estradiol testing to look for causes of:

• abnormal menstrual periods
• abnormal vaginal bleeding
• infertility in women

Your doctor may also order an estradiol test if your menstrual cycle has stopped and you’re having symptoms of menopause. During and after menopause, a woman’s body will gradually produce less estrogen and estradiol, contributing to the symptoms experienced during menopause. A test of your estradiol level can help your doctor determine if you’re preparing to enter menopause or you’re already going through the transition.

The estradiol test can also indicate how well the ovaries are working. Therefore, your doctor may also order this test if you have symptoms of an ovarian tumor. The symptoms include:

• bloating or swelling in your abdomen
• trouble eating due to feeling full after eating a small amount of food
• pain in your lower abdominal and pelvic area
• weight loss
• frequent urination

If you’re pregnant or you’re on infertility treatments, your doctor may order an estradiol test to help keep track of your progress.
An estradiol test usually isn’t used alone to make a diagnosis. However, the results of this test may help your doctor decide if further testing is necessary.
People undergoing transgender hormone therapy may receive estradiol. If so, their estradiol levels may be regularly tested and monitored by their doctors.

What are the risks associated with an estradiol test?

The risks associated with having an estradiol test are low. They include:

• multiple punctures due to trouble finding a vein
• excessive bleeding
• feeling lightheaded
• fainting
• hematoma, which is an accumulation of blood under your skin
• infection at the needle puncture site