Estradiol blood tests help in measuring the levels of estrogen hormones. These hormones are uniquely responsible for the growth and development of women’s sexual characteristics and reproduction. Estrogen is one of the most commonly known and discussed of all hormones in the human body. The term “estrogen” includes a group of chemically similar hormones namely Estrone, Estradiol (the most abundant in women of reproductive age) and Estriol. Overall, the estrogen hormone is produced in the ovaries, fat tissues, and adrenal glands. Levels of this crucial hormone in women’s reproductive age fluctuate from 10–300 pg/mL, depending on the timing of the monthly cycle. For ovarian reserve testing, specialized doctors usually assess E2 levels at their early in the monthly cycle, at days 2 or 3 of the same.
More particularly, estradiol and estrone forms are produced primarily in the ovaries in premenopausal women, while estriol hormone is produced by the placenta during pregnancy. In women, estrogen hormone helps in circulating in the bloodstream and binding to estrogen receptors on cells in targeted tissues. It thereby affects not only the breasts and uterus, but also the liver, heart, brain, bone, and other tissues. Estrogen helps in controlling the growth of endometrial lining during the first phase of the menstrual cycle, thus causing changes in the breasts during adolescence and pregnancy. This also helps in regulating several other metabolic processes, including cholesterol levels and overall health of the individual including that of bones.
This article gives detailed information about:
- What is Estradiol blood test?
- What is the role of Estradiol in fertility levels?
- What is the significance of Estradiol in pregnancy?
- What are the uses of Estradiol blood test?
- What are the indications for Estradiol hormone test?
- How Estradiol test is performed?
- How to prepare for Estradiol test?
- What are the risks associated with Estradiol test?
- Frequently Asked Questions about Estradiol Hormone Blood Test
What is Estradiol blood test?
An estradiol blood test is helpful in measuring the amount of estradiol hormone in the blood. Estradiol hormone test is called as an ‘E2 test’. Estradiol test is a simple blood test. E2 or estradiol hormone is one of the four major types of the hormone estrogen that is chiefly produced by the ovaries. It is the form of estrogen hormone which is scientifically known as 17 beta-estradiol. Hormone estradiol is made by adrenal glands, testes, ovaries, and breasts. When a woman is pregnant, the Estradiol hormone is also made by the placenta. The right estrogen levels are crucial for the reproductive health of both men and women. Imbalance in the hormonal levels of Estradiol can lead to certain medical and reproductive health problems, like urinary tract infections, weak bones, and even depression. Doctors may recommend an estradiol test if they are concerned about a woman’s fertility, puberty, or menopause phase.
Role of Estradiol in Fertility Levels:
Estrogen hormones are a group of steroids that are responsible for the development and proper functioning of reproductive organs. These hormones also manage the formation of secondary sexual characteristics in females. Estradiol, along with another hormone, progesterone, helps in regulating the menstrual cycle. These hormones are also involved in the growth of breasts and the uterus and help in maintaining a healthy pregnancy until the delivery of the baby. In females, estradiol hormone acts majorly as an effective growth hormone for the reproductive system including fallopian tubes, vagina, endometrium, and cervical glands. Estradiol hormone helps in enhancing the growth of the womb’s muscle layer, the myometrium. In addition, the hormone also helps in maintaining oocytes (eggs in the ovary) and triggering a series of events that lead to ovulation. Estradiol hormones are considered as potent sex hormones for women as they assist in the proper functioning of the reproductive system. They are also found in men and play a vital role in bone metabolism and growth in both sexes.
Estrogen blood tests help in measuring the three components of this hormone: Estrone (E1), Estradiol (E2), or Estriol (E3) in the blood or urine. Estrone (E1) is either directly converted from androstenedione (from the adrenal gland) or indirectly from other androgens. E1 is also produced by the ovaries, testicles, placenta, and adipose (fat) tissues. E2 and E1 can be easily converted into each other as and when needed which makes estrogen a useful hormone for the body. E1 is an important endogenous primary estrogen. It is significantly present both in men and postmenopausal women. Estradiol (E2) is primarily produced in the ovaries under stimulation of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) in pre-menopausal women and in the testicles in men. E2 is converted from E1 in post-menopausal females.
It is the most effective estrogen and the one that is present in the highest concentration in non-pregnant and pre-menopausal women. E2 hormone levels vary depending on a woman’s age and reproductive system. These hormones are a good marker of ovarian function in women. Estriol (E3) hormone is produced by the placenta, with concentrations elevating throughout a woman’s pregnancy. These increasing levels of E3 hormones are an indication of the health of developing a baby. Estriol is one of the most important parts of the second-trimester maternal serum screening as suggested by the top fertility doctors. This screening test is performed to analyze fetal risk due to certain chromosomal defects. Comparatively lower levels of E3 are present in non-pregnant women or men.
Estrogen in Girls and Women:
The types and amounts of estrogen normally present in a woman’s blood vary throughout her lifetime. Levels of this hormone vary during each monthly cycle and during pregnancy. Secondary sexual characteristics in women such as public and armpit hair also begin to grow when the levels of estrogen hormone rise. Many organ systems, including the cardiovascular and musculoskeletal systems and the brain, are affected with the functioning of the hormone estrogen.
Levels of Estradiol (E2) and Estrone (E1) hormones are usually high at this time but fall within a few days. Concentration levels are normal during early childhood. After the birth of a baby, oxytocin hormone that plays a vital role in labor continues to contract the womb. This restricts the blood flow to the womb and prevents bleeding. Oxytocin hormone is often called the ‘love hormone’, which is associated with feelings of motherhood and bonding between mother and baby.
Concentrations of E2 and E1 begin to rise as a child reaches his or her puberty. These estrogens are responsible for the development of uterine growth, breasts, and (with other hormones) the onset and regulation of menstruation cycle. A moderate amount of E1 hormone is present from the time of puberty to menopause. This concentration varies during the day but is otherwise relatively constant.
The menstrual cycle of a woman is approximately 28 days long when the average days are taken into consideration. The cycle usually consists of two phases, follicular phase (day 1-14) and luteal phase (day 15-28). During each cycle, Estradiol (E2) hormone and several other hormones normally increase and then fall in a particular sequence.
Estriol (E3) is the main estrogen present in a woman’s body during pregnancy. It is produced by the placenta, begins to rise in the 8th week of pregnancy, and continues to rise throughout the period of pregnancy. A sharp increase of E3 hormone happens approximately 4 weeks prior to the onset of labor. Estriol circulating in a pregnant woman’s blood is quickly cleared out of the body. Each measurement of estriol hormone describes the current status of placenta and fetus. Also, there is a natural daily variation in estriol concentrations. E1 hormones also rise during pregnancy, increasing as much as 10-fold between weeks 24 and 40 of pregnancy. Post delivery, E1 falls and E3 again becomes significantly undetectable. This hormone regulates progesterone, which helps in protecting pregnancy. It also encourages one of the major processes of fetal maturation. Without it, a fetus’s organs and tissues cannot mature.
Estrone (E1) is the key estrogen present during menopause. E2 concentrations significantly decline as ovarian production diminishes and eventually stabilize at a low level.
Estrogen in Boys and Men:
The term “estrogen” actually refers to any of a group of hormones which are chemically associated with the estrogen hormone; estrogenic hormones are sometimes wrongly interpreted to as exclusively female hormones when in fact the hormone is produced in both men and women. Estrogen plays an important role in sexual function and testosterone is the primary hormone.
Significance of Estradiol in Pregnancy:
During a woman’s reproductive years, the pituitary gland in the brain generates hormones that allow a new egg to be released from its follicle each month. As the follicle develops, it produces estrogen, which causes the thickening of the endometrial lining of the uterus. Progesterone hormone production rises after ovulation in the middle of a woman’s cycle for preparing the lining to receive and nourish a fertilized egg so it can successfully develop into a fetus. If fertilization does not occur, estrogen and progesterone levels drop sharply which results in the lining of the uterus breaks down and menstruation occurs in the woman. Estradiol hormone levels obtained on the 4th day of gonadotropin therapy were highly predictive of successful ovulation induction and pregnancy outcome in monthly cycles using the luteal phase.
If fertilization happens, estrogen and progesterone hormones work together to prevent the occurrence of regular ovulation during pregnancy. Birth control pills (oral contraceptives) take advantage of this effect as they start regulating hormone levels. This also results in the production of a very thin endometrial lining, which is unreceptive to a fertilized egg. Plus, they are responsible for thickening cervical mucus in order to prevent sperm from entering the cervix and fertilizing an egg. Oral contraceptives containing estrogen hormone also relieve menstrual cramps and some perimenopausal symptoms and regulate menstrual cycles in women with Polycystic Ovarian Syndrome (PCOS). Furthermore, various research studies indicate that contraceptive pills have the potential to reduce the risk of ovarian, uterine, and colorectal cancer.
Uses of Estradiol hormone Test:
Estradiol blood tests are used to evaluate a deficiency or excess in a woman. This helps diagnose a variety of medical conditions related to this imbalance. They may also be used to help to ascertain the timing of a woman’s ovulation. These tests are also recommended to monitor the health status of the developing baby and placenta during pregnancy. In a man, estradiol testing is performed to detect a hormonal increase and reasons for its increase. The three components of hormone estrogen: Estrone (E1), Estradiol (E2), and Estriol (E3) have their unique uses. Below are explained different uses of estradiol test:
- Diagnosing early onset-puberty or delayed puberty
- Investigating menstrual abnormalities such as amenorrhea, abnormal vaginal bleeding, and infertility
- Monitoring follicle development prior to In Vitro Fertilization (IVF) treatment
- Monitoring menopausal hormone replacement therapy (HRT) which is given to reduce symptoms related to estrogen deficiency
- Detecting estrogen-producing tumors
Indications for Estradiol Hormone Test:
A fertility doctor may order an estradiol test if female or male sex characteristics are not developing at the desired rate. In cases where estradiol is higher than normal, the situation indicates that puberty has happened earlier than usual. This condition is known as ‘precocious puberty’. Presence of lower levels of estradiol hormone indicates a condition of late occurrence of puberty.
In Girls and Women
Estradiol (E2) and/or Estrone (E1) hormone blood testing in girls and women is recommended in the following cases:
- A girl’s sex organs develop earlier or later than usual
- A woman having symptoms such as abnormal or lack of menstrual cycles and abnormal vaginal bleeding after menopause
- Female factor infertility; a series of estradiol test over the course of a woman’s monthly cycle are performed to monitor follicle development prior to ART procedure (timed with a surge in estradiol).
- A woman experiencing symptoms of menopause, including night sweats, insomnia, hot flashes, and/or irregular or lack of menstrual periods.
- A menopausal woman undergoing hormone replacement therapy (HRT) is also recommended periodically to get her estrone levels monitored.
Estriol (E3) testing in women is recommended in the following cases:
- During pregnancy, a fertility doctor recommends serial estriol samples to look for a certain rise or fall in the estriol level over time.
- Unconjugated estriol hormone is often measured during 15th to 20th week of gestation as part of the triple/quad screening.
In Boys and Men:
Estradiol (E2) and/or Estrone (E1) testing in boys and men is recommended in the following cases:
- A boy has delayed puberty, characterized by delayed growth of muscle mass, slow or delayed growth of testicles and penis and lack of deepening of the voice or growth of body hair.
- A man experiencing signs of feminization, like enlarged breasts.
How Estradiol test is performed?
Estrogen hormone tests can be performed in blood, urine, or saliva. Blood or urine test is usually performed at the doctor’s office or lab. Saliva tests can be performed even at home after following the advice of the doctor.
For a blood test:
A health care professional takes a blood sample from a vein in the patient’s arm, using a small needle. After the needle is inserted, a small amount of blood is collected into a test tube or vial to be sent for further tests. A patient may feel a little sting when the needle goes in or out. This procedure takes usually less than five minutes which proves to be time-saving for the patients.
For a urine test:
For this test, the health care provider asks patients to collect a certain amount of urine passed in a 24-hour period. This is called a ’24-hour urine sample test’. For a urine test, the laboratory professional hands over a container to collect urine and patient need to follow instructions on how to collect and store the samples for further process.
How to Prepare for the Test?
While some hormone blood tests require the patient to avoid eating or drinking beforehand, people undergoing an estradiol test do not need to make any such specific preparation. Women, who are taking any medication, like hormone therapy medication or birth control or, they must let their doctor know before undergoing the test. Certain forms of medication could have a significant impact on the results of the estradiol test.
Other tests associated with Estradiol Test:
Depending on the patient’s unique medical condition, the doctor may also recommend other tests. These tests may include:
- Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH), for menopausal issues and treatment
- FSH and LH, for early puberty
- FSH, thyroid-stimulating hormone/free thyroxine (TSH/FT4), and prolactin, a hormone required for breast milk production, in cases of absent periods
- TSH, FSH, prolactin, and LH, for both female and male factor infertility issues
Risks associated with Estradiol Test:
An estradiol test is a simple blood test, and the risks associated with this test are low. However, any test involving a needle carries certain risks, such as:
- Blood building up under the skin
- Pain and soreness at the site afterward
- Feeling dizzy, fainting or lightheaded
- Multiple punctures if a doctor is unable to find a suitable vein
- Hematoma (blood accumulated under the skin causing a bruise or lump)
Estradiol hormone test range:
Normal estrogen results depend majorly upon the gender and age of the person being tested. With women, it also depends upon their monthly cycle or whether they are pregnant. The reference range varies somewhat between laboratories, both in normal values listed and in units used. Both rising and falling levels of estrogen are carefully observed in several medical conditions. Expert guidance must be used in the interpretation of hormones Estrone, Estradiol, and Estriol results as there is a variation in levels on a day-to-day basis and throughout a woman’s menstruation cycle. A healthcare provider who is monitoring a woman’s hormones will look at trends in the levels, increasing or decreasing over time in conjunction with the monthly cycle or pregnancy rather than examining single values. According to some reputed medical laboratories, a normal level of hormone Estradiol (E2) for menstruating women ranges from 15 to 350 picograms per milliliter (pg/mL). For postmenopausal women, these levels should be lower than 10 pg/mL. Estradiol level that is higher than normal indicates the presence of early puberty.
Estradiol Normal Range:
- Male: 10 – 50 pg/mL
- Female (premenopausal):30 – 400 pg/mL
- Female (postmenopausal):0 – 30 pg/mL
What does abnormal Estradiol Test Result mean?
Lower levels of estradiol test result indicate the following conditions:
- Low estrogen levels due to sudden and rapid weight loss
- Low levels of pituitary hormones
- Ovarian failure
- Failed pregnancy
- Turner syndrome, a chromosomal defect that can lead to infertility
Higher levels of estradiol test results indicate the following conditions:
- Tumors in the adrenal glands, ovaries or testicles
- Liver damage
Frequently Asked Questions about Estradiol Hormone Blood Test:
Q. What does estradiol mean in a blood test?
An estradiol test is a simple blood test which measures the amount of hormone estradiol in the concerned patient’s blood. Estradiol hormone is also known as ‘E2’. It is one of the four types of estrogen which is produced by the ovaries.
Q. Is fasting required for Estradiol test?
In both men and women, low levels of estradiol are related to osteoporosis. Fasting is not required for this estradiol blood test. Take medications as prescribed by the medical specialist. For those patients who are supplementing with any hormones, doctors suggest taking them approximately 2-3 hours prior to having the blood drawn.
An estrogen hormone is considered critical in different aspects of overall health. The estradiol hormone test will often be the first step towards assessing solutions to improve several different aspects of a person’s well-being. Today, an appreciating percentage of all babies are born with assisted reproductive technology. These statistics are expected to rise in the near future as mean maternal age continues to rise. While the workup for infertility can be extensive, advanced medical laboratory tests can prove to be helpful in determining a primary diagnosis and assess associated ovarian reserve. Most importantly, the results of these tests give a predictive framework for evaluating and treating infertility. As there is a progression in the advancement in technology, laboratory testing will undoubtedly become a more accurate and trustworthy predictor of response to medical conditions. This will make the treatment of infertility safer and more efficient for women. Estradiol blood test helps a fertility doctor to evaluate and diagnose fertility issues or menopause status in the patient. For a woman, a fertility specialist may suggest several blood samples drawn over the course of her monthly cycle. This is done to efficiently check for a woman’s estradiol levels.
SOURCES AND REFERENCES:
- Fertility Testing – AACC Aacc.org, 10 June 2019
- What Is an Estradiol Test and Why Is It Used – Medical News Today Medicalnewstoday.com, 10 June 2019
- What does Estradiol do – News Medical Life Science News-medical.net, 10 June 2019
- Estrogens Effects on the Female Body Urmc.rochester.edu, 10 June 2019
- Hormones of Pregnancy and Labour – Your Hormones Yourhormones.info, 10 June 2019