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What is Estradiol?
Estradiol is a type of estrogen, the major sex hormone in women. It is secreted by the ovarian follicles. As the follicles grow and develop each month, they produce estradiol. This sets the rest of the reproductive cycle in motion.
Why Would You Have Estradiol Checked?
A blood test to check estradiol levels is one of the most common fertility tests. One reason to have your estradiol levels checked is to determine your ovaries’ ability to produce eggs (which is known as ovarian reserve).
It can also help to determine if your follicle stimulating hormone (FSH) test was accurate or not. Estradiol suppresses FSH. If your FSH levels are normal but your estradiol levels are high, this indicates that the estradiol is artificially suppressing FSH levels.
If you have already begun fertility treatment, your estradiol levels may be checked to see how the ovaries are responding to stimulation. You may also have the test if you’ve missed a period but aren’t pregnant.
When Are Estradiol Levels Checked?
You will probably have your estradiol levels checked on day 3 of your menstrual cycle, along with FSH levels. It involves drawing blood from your arm. The blood test is looking for the levels of the hormone estradiol in your bloodstream.
What Do Estradiol Levels Mean?
High levels of estradiol indicate that you might have a problem with your ovarian reserve. It could also mean that the estradiol is suppressing FSH. Either of these things could mean that you will have more trouble getting pregnant, more trouble ovulating (even with treatment) and reduced success with IVF. In rare cases, high levels of estradiol could indicate an ovarian tumor or hyperthyroidism.
If your estradiol levels are low, it can indicate polycystic ovary syndrome (PCOS) or hypopituitarism. Women with eating disorders or extreme endurance exercising may have low levels of estradiol. After menopause, estradiol levels are also low.
Estrogen-replacement therapy might be used in combination with clomiphene (Clomid) to help improve cervical mucus or uterine lining to make the body more hospitable to pregnancy. IVF treatment with lupron flare protocol or assisted hatching to try to compensate for poor quality and/or quantity of ovarian reserve.
Because high estradiol levels indicate poor ovarian reserve and poor response to fertility medications, you and your fertility doctor may ultimately need to discuss whether IVF with your own eggs is a viable option for you and your partner. You may need to discuss the possibility of using a donor egg with IVF.