What is Estradiol?
Estradiol is a type of estrogen, the major sex hormone in women, and 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 doctor may check your estradiol levels 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.
You will probably have your estradiol levels checked via a blood test on day 3 of your menstrual cycle, along with your FSH levels.
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 who practice extreme endurance exercising may have low levels of estradiol. After menopause, estradiol levels are also low.
Estrogen pills, patches, suppositories, and even injections can be prescribed to support fertility treatments. In patients with a thin endometrial lining, estrogen can be used to support growth and development and promote receptivity.
Estrogen patches also can be used prior to the start of an IVF cycle as part of an “estrogen priming protocol.” Prior to replacement of a frozen embryo, patients are often placed on estrogen for weeks to prepare the uterus.
Dr. Alan Copperman is a board-certified reproductive endocrinologist and infertility specialist with a long history of success in treating infertility and applying fertility preservation technologies. He serves as Medical Director of Progyny, a leading fertility benefits management company, and co-founded and serves as Medical Director of RMA of New York, one of the largest and most prestigious IVF centers in the country. Dr. Copperman’ is also the Vice Chairman and Director of Infertility for the Icahn School of Medicine at Mount Sinai, and Chief Medical Officer of Sema4, a health information company. Dr. Copperman has been named to New York magazine’s list of Best Doctors 17 years in a row. He has been recognized by his peers and patient advocacy organizations for his commitment to patient-focused and data-driven care. He has published more than 100 original manuscripts and book chapters on reproductive medicine and has co-authored over 300 scientific abstracts on infertility, in vitro fertilization, egg freezing, ovum donation, and reproductive genetics.