Estrogen in Women: What It Does & What Levels to Look for
Whether you are trying to conceive (TTC) or simply trying to maintain good hormone health, estrogen is one of the most crucial hormones to pay attention to. From your cholesterol to your bones, estrogen plays dozens of distinct, yet equally important roles in the female body.
In order for estrogen to play its proper role in the body, you need to maintain healthy levels of this essential hormone. Estrogen levels that are either too low or too high can result in unpleasant symptoms that can potentially become dangerous in the long-term.
Read on to learn more about estrogen, including what it does for your body, what ideal estrogen levels look like, and how to tell if your estrogen levels are out of balance.
What is estrogen?
Estrogen is a primary sex hormone found in women’s bodies that helps regulate the menstrual cycle, fertility, and overall health. It is mainly produced in the ovaries, though it can be found in small amounts in the adrenal glands and fat (or adipose) tissue as well. Sometimes, the ovaries produce too much or too little estrogen, which can negatively impact fertility and well-being.
Types of estrogen
- Estradiol is the most common type of estrogen found in women of childbearing age
- Estrone is the most common type of estrogen produced after menopause
- Estriol is the most common type of estrogen produced during pregnancy (more on estriol vs. estradiol here)
In general, when they talk about “estrogen levels” in the body, people are talking about levels of estradiol, which fluctuate naturally throughout the menstrual cycle.
What does estrogen do?
Estrogen is responsible for female sexual development, triggering the growth of breasts, pubic hair, and other sex characteristics during puberty. This hormone also plays an important role in maintaining your reproductive health by controlling the growth of the uterine lining at the beginning of your menstrual cycle and during pregnancy.
However, estrogen also plays an important role in your overall health. Estrogen regulates your bone and cholesterol metabolism, as well as your body weight, glucose metabolism, and insulin sensitivity.
Normal estrogen levels
Estrogen levels naturally fluctuate throughout the menstrual cycle. Measuring your body’s estrogen levels can help you get a better grasp on your fertility throughout the month. Our new Mira fertility monitor measures the trends in your estrogen levels in relation to your levels of luteinizing hormone.
In women of reproductive age, estrogen levels are lowest during the menstrual period. During your period, the unfertilized egg, released during ovulation, dies off and is shed, along with the uterine lining. Estrogen levels fall when the sac that previously held the egg, the corpus luteum, degenerates during menstruation.
A normal level of estradiol is <50 pg/mL during the menstrual period. Estradiol levels should be lowest during the menstrual period when compared to any other phase of the menstrual cycle.
The follicular phase is the stretch of time between menstruation and ovulation. This period is named for follicles, the sacs in the ovaries that grow and house eggs and estrogen levels gradually rise during this phase, reaching their peak just before ovulation.
During the follicular phase, many follicles develop eggs. Eventually, a dominant follicle emerges that will release an egg during ovulation. One or more follicles may also become harmless functional cysts.
From around day five of the menstrual cycle to around day 14, estradiol levels gradually rise from approximately 19 pg/mL to 140 pg/mL before peaking at ovulation.
Estrogen levels reach their highest peak just before ovulation. Women who are TTC can predict their fertile window by measuring the peak in estrogen prior to ovulation using a digital fertility tracker like Mira.
Ovulation takes place roughly halfway through the menstrual cycle and indicates when women are at their most fertile. During ovulation, one of the ovaries releases an egg, which travels down the fallopian tube. The egg lives for only 24 hours before degenerating. If it is not fertilized in that 24-hour period, the egg will be shed during menstruation, approximately 14 days later.
Just before ovulation, normal estradiol levels can range from 110 to 410 pg/mL. Ideally, estradiol levels should reach about 400 pg/mL prior to ovulation. Estradiol levels should be at their highest right before ovulation when compared to any other phase of the menstrual cycle.
After ovulation, the follicle that released an egg becomes the corpus luteum and gradually degenerates. The luteal phase is the period after ovulation, named for the corpus luteum. There is a rapid increase in progesterone, the other major female sex hormone, during the luteal phase, accompanied by a moderate increase in estrogen. The luteal phase generally lasts anywhere from 10 to 17 days before menstruation begins (read our tips on lengthening the luteal phase here).
Estrogen levels steadily increase during pregnancy. They increase most rapidly during the first trimester, leading to negative side effects like morning sickness. During the second trimester, the rise in estrogen contributes to milk duct development in the breasts. Finally, during the third trimester, estrogen levels reach their peak. These levels rapidly decline after delivery.
Estrogen levels rise during pregnancy for several reasons. Firstly, they are produced by the placenta, which houses the growing fetus. Secondly, the sharp rise in estrogen during pregnancy prevents ovulation, since it is no longer necessary when an egg is already fertilized.
Usually, estradiol is the most common form of estrogen found in the body; however, during pregnancy, the body produces high levels of estriol. In a normal pregnancy, estriol levels rise from about 4 nmol/L at 15 weeks to 40 nmol/L at delivery.
After menopause, the body stops producing as much estrogen and starts to only produce small amounts of estradiol and estrone. The low levels of estrogen present in the body after menopause are responsible for unpleasant symptoms like hot flashes, fatigue, low libido, and depression.
Hormone replacement therapy, which contains estrogen, can be used to treat menopausal symptoms. According to the FDA, when it comes to dosage, patients should take only very small amounts of estrogen.
The Women’s Health Initiative states that using hormone replacement therapy has some health risks. Hormone replacement therapy may increase the risk of breast cancer, heart disease, and stroke. Additionally, it should not be used by women with a high risk of osteoporosis or other bone diseases.
After menopause, a normal estradiol level is <35 pg/mL. A normal estrone level is between 10 and 50 pg/mL. It’s worth noting, however, that hormone replacement therapy may cause these levels to increase slightly, relieving some of the symptoms of menopause.
What is high estrogen in women?
Symptoms of hormone imbalance manifest when certain hormones are over- or under-produced by the body. High estrogen levels are one of the most common hormonal imbalances found in women of childbearing age. Excess estrogen can manifest from a health condition, such as endometriosis or obesity, or in response to certain medications, like antibiotics or hormonal birth control.
When estrogen levels are healthy, you should not experience any major symptoms associated with hormone imbalance. You should be able to maintain a healthy weight, experience a normal level of sexual desire, and have only normal fluctuations in mood, with no signs of clinical anxiety or depression.
Some of the symptoms you may experience when your estrogen levels are too high include:
- Weight gain in the hips and thighs
- Heavier or lighter periods than usual
- Worsening of premenstrual syndrome
- Uterine fibroids and/or fibrocystic breasts
- Fatigue, loss of sex drive, and/or changes in mood
Not all causes of high estrogen are within our control — but thankfully, many are.
Environmental, dietary and lifestyle factors can all contribute to high levels of estrogen. By controlling your exposure to risk factors, you can decrease the likelihood that you will continue to experience symptoms of high estrogen.
If you are experiencing high levels of estrogen, you may want to try implementing the following lifestyle changes to improve your chances of a healthy conception:
- Choose organic foods whenever possible. Exposure to certain toxins can throw hormone levels out of balance. Choosing organic foods minimizes your exposure to pesticides, which is an easy way to manage your body’s toxic load.
- Avoid toxins in personal care products. Likewise, you should also minimize your exposure to toxins in personal care products. Common culprits include parabens and sulfates, which are found in everything from shampoo to makeup.
- Minimize phytoestrogens in your diet. Many foods contain phytoestrogens, which mimic the role of estrogen in the body and contribute to symptoms of high estrogen. Examples of these foods include wheat and soy. You should also choose responsibly raised meat and dairy products, as conventional meat and dairy may contain hormones (which many factory farmers administer to animals to speed the fat growth process).
- Manage stress in your life. Chronic stress has a massive effect on your production of the stress hormone cortisol, which can lead to an imbalance of sex hormones. Meditation and exercise are two healthy ways to manage stress that you may consider adopting in your everyday routine.
- Consider a healthy weight loss. If you are overweight or obese, losing a healthy amount of weight (as determined by your doctor) may help reduce estrogen levels in your body, as fat tissue naturally produces its own estrogen. Estrogen then leads the body to store even more fat, which perpetuates the cycle of overweight and hormone imbalance.
What is low estrogen in women?
Hormonal imbalances like low estrogen levels can create challenges for people who are looking to conceive or get rid of uncomfortable symptoms. It’s important to recognize when low estrogen is contributing to infertility or other symptoms so you can take action to treat this condition.
Female infertility may sometimes be a sign of low estrogen levels. One of the leading causes of female infertility is infrequent ovulation. This can result in missed or irregular periods that impact your ability to get pregnant.
Low estrogen may be a cause of infrequent ovulation since estrogen plays a role in triggering the ovaries to release an egg. As a result, reversing low estrogen levels can help you ovulate more regularly and improve your chances of conceiving naturally.
Suspect your estrogen levels may be too low? Keep an eye out for the following symptoms:
- Missed or late menstrual period
- Fatigue and/or trouble sleeping
- Depressed mood
- Painful sex due to a lack of lubrication
- Frequent urinary tract infections due to the thinning of the urethra
- Breast tenderness
- Headaches or worsened migraines
- Hot flashes and/or night sweats
- Low libido
Estrogen levels may also drop due to extreme weight loss or excessive exercise associated with an eating disorder. Contact a psychological professional if you suspect that you or someone you love may be suffering from an eating disorder.
First, it’s important to recognize that not all estrogen is created equal. Some types of estrogen have a negative effect on overall health and may increase your risk for health conditions such as breast cancer. Other types, however, are healthy for the body and help maintain healthy menstrual cycles and fertility.
Exercise and diet play a large role in improving estrogen levels. Incorporating certain foods into your everyday diet may help you raise estrogen levels. These foods function as phytoestrogens, mimicking the role of estrogen in your body and helping your body get rid of bad estrogen in the body (so you can raise levels of good estrogen!). Some of these foods include:
- Soy foods (ex: tofu and tempeh)
- Dried fruits
- Alfalfa sprouts
While regular exercise can help the body keep bad estrogen levels in check, it’s important to refrain from over-exercising. Too much exercise (such as the excessive exercise seen in some eating disorders) can lower estrogen levels and increase testosterone, leading to irregular or missing periods and impacting fertility. If you have low estrogen levels, you may want to consider nixing heavy cardio and weight-lifting in favor of gentler forms of exercise, such as long walks or yin yoga classes.