Estrogen, progesterone and testosterone are three key hormones in women. Here we discuss their role in women's health and hormone testing.
There are over 50 hormones in our body.
These are chemical messengers that transfer signals between different parts of the body.
Hormones touch almost every aspect of our life including sleep, metabolism, body temperature, muscle & bone strength, pregnancy, and even the process of getting old.
Hormone imbalance means the body is producing too much or too little compared to the expected levels.
Nowadays, at home blood or saliva hormone test kits are popular to check hormone imbalance. But one should understand the symptoms and know what to look for.
Some of the hormones, especially the sex hormones for reproductive health fluctuate with age and monthly menstrual cycles.
The plot below shows hormone imbalance in women is more common around puberty and menopause.
Figure 1: Hormone fluctuations occur the most during puberty and menopause. It plots progesterone levels, one of the female hormone levels, by age (Trabert, 2020).
On an average, a woman has about 35 years of reproductive life. One of the key features of these years is the monthly menstrual period that starts with 'bleeding' (or menses).
The cycles start in puberty, around the age of 13 years, and continue until menopause.
Each menstruation cycle includes significant rise and fall in hormone levels as a woman's body prepares for a possible pregnancy.
The figure above shows women's hormones are also affected by age. Clearly, both puberty and menopause add complications. Pregnancy plays yet another important role.
That's why, any discussion of hormone imbalance in women should always include their age, menstrual cycle, and pregnancy status.
Here we review three female sex hormones that play major role in women's health: estrogen (whose most common form is estradiol, E2), progesterone (Pg) and testosterone (T).
The other two key hormones produced by the ovaries are FSH (follicle stimulating hormone) and LH (luteinizing hormone), which we will be discuss separately.
Estradiol is the most common form of estrogen measured in a lab test.
Normally, a women's hormone test checks the following key female sex hormones:
• Estrogen - means 'one that generates verve or desire in women'. A woman's monthly cycle is attributed to estrogen. There are four forms of estrogen:
○ Estrone (E1) - is predominant estrogen after menopause.
○ Estradiol (E2) - is common during menstrual life of a woman; people often use estradiol and estrogen interchangeably.
○ Estriol (E3) - is predominant estrogen during pregnancy and helps in childbirth and lactation.
○ Estetrol (E4) - is less common and only produced in pregnancy.
• Progesterone (Pg) - means 'one that helps carry a baby or supports gestation'. It is the hormone of pregnancy and fluctuates significantly in menstrual cycle as well pregnancy.
• Testosterone - is important to build muscles and bones. Normal testosterone levels naturally decline with age in both women and men.
• Cortisol - this stress hormone has a 24-hour cycle and not significantly affected by gender or menstrual cycle.
• DHEA - is a precursor to many other hormones. DHEA (dehydroepiandrosterone) levels also fall with age.
• Estrogen vs Progesterone Ratio - is often used as a marker of health. Ideal values are between 100 to 500 in premenopausal women but much higher (150-1000) in those supplementing.
To understand any imbalance, we need to first learn how hormones change during menstrual cycle, with age, and during pregnancy.
Let's first discuss changes in estrogen and progesterone levels during a menstrual period.
Figure 2. Hormone fluctuations during a cycle. Levels of estrogen, progesterone and testosterone during the follicular and luteal phases (from Glover 2013). Days 19 to 21 are recommended for sample collection in hormone testing.
A woman's menstrual cycle is said to be about 28 days (in reality, it's about 29.1 days, based on data from thirty thousand cycle records).
The first half before ovulation is follicular phase, when ovaries make follicles that will become eggs. It starts with first day of menses or bleeding.
The second half of about 14 days is luteal phase, when sharp rise and drop in progesterone and estrogen levels prepare the uterus for a possible pregnancy.
The second half of menstrual cycle, called luteal phase, is relatively stable at 14 days. It's the first half, follicular phase, that causes variations in cycle.
The chart above shows these two phases of a menstrual cycle and changes in estrogen, progesterone and testosterone levels.
Below we plot the same progesterone, estrogen chart over 28 days to show the cyclical nature of hormone fluctuations during the period.
Overlapping the key hormones together clearly shows what happens to estrogen, progesterone, LH and FSH levels during the cycle and how ovulation is dependent on the timing of each hormone.
It also shows two peaks of estrogen during the follicular and luteal phases, and the progesterone vs estrogen comparison after ovulation.
Figure 3. Changes in FSH, LH, estrogen, progesterone hormone levels week by week during a menstrual cycle. Ovulation happens within hours after the LH and FSH levels peak, and within a day of first estrogen peak. Progesterone levels only start rising after ovulation, and both estrogen and progesterone peak during the luteal phase around day 20 of the cycle.
In short, here's what happens during a menstrual cycle week by week:
Week 1: A menstrual cycle starts with bleeding which lasts about 4-6 days (but may vary between 2 and 8 days). Total discharge is around 30 ml but can go up to 60-80 ml. Both estradiol and progesterone levels remain low (below 5 ng/mL).
Week 2: After the bleeding stops, estrogen levels rise sharply until ovulation. The role of estrogen is to prepare the uterus and ovaries for ovulation, which happens around day 14 of the menstrual cycle.
After the estrogen spike, FSH and LH hormones surge to help the ovaries release the egg. We discuss role of FSH and LH in a separate article.
Week 3: The luteal phase starts as progesterone levels continuously rise to prepare the body for a potential pregnancy. Estradiol levels drop after ovulation but temporarily rise again. This is the best time to collect a sample to understand the estrogen and progesterone ratio, as an indicator of reproductive health.
Week 4: Both progesterone and estradiol levels start dropping if there is no pregnancy and next cycle begins. But if a pregnancy is successful, progesterone levels continue to rise to help the uterus prepare for the baby. Estrogen levels remain low during first trimester, then rise to help in childbirth and lactation.
There is little change in testosterone levels during the menstrual cycle, with a small peak around ovulation.
If you are pregnant, it's natural to see progesterone levels rise.
During regular menstrual cycle, progesterone levels rise in luteal phase to about 30 mg/mL.
But once you get pregnant, the levels continue to rise and don't drop as they do when bleeding starts.
Figure 4. Pregnancy hormones week by week. Progesterone levels start rising in first trimester but estrogen levels remain flat and only start to rise in second trimester.
After about 10 weeks of pregnancy, the placenta starts releasing progesterone, which continues to rise to ten-fold until delivery.
Progesterone has several roles in pregnancy:
It supports a baby's development and growth in the uterus until birth.
It helps uterus enlarge to accommodate the growing baby.
It blocks production of hormones responsible for next menstrual cycle and ovulation, such as FSH hormone, LH hormone.
Estrogen levels rise later, in second trimester as the plot above shows. The dominant forms are now estradiol (E2) and estriol (E3). A new form, estetrol (E4), is only produced during pregnancy.
Estrogen is responsible for darkening the skin. Higher estrogen levels during pregnancy make browner & yellower skin (called the 'mask of pregnancy' - in third trimester).
Most women have about thirty five years of menstrual periods, which tend to become irregular with age.
The average age of final bleeding before menopause is about 51 and half years.
But menopausal transition, also called perimenopause, can last 2 to 6 years.
During this transition, cycles often become irregular, with fewer and fewer periods. The hormone imbalances cause symptoms similar to infertility or PCOS (polycystic ovary syndrome). The nature of bleeding discharge may also change.
Figure 5. Change in estradiol and FSH levels around menopause (from Santoro & Randolph, 2011). The average age of menopause is about 51 years. The steep rise in FSH levels is the hallmark of a menopause test.
Here are few other hormone changes that accompany menopause:
FSH levels in menopause are high. One of the earliest signs of perimenopause is increase in FSH levels, which start to rise about six years before menopause.
Though the second half of cycle (luteal phase) is stable, the first follicle phase becomes shorter and shorter as a woman reaches menopause. Levels of Inhibin B also drop, which are markers of quantity and quality of follicles.
Estradiol levels in women remain stable but then start declining in last 2 years before menopause.
Progesterone levels start to fall about seven-percent per year until menopause; the levels become very low after 1-2 years of menopause.
After menopause, the adrenal glands still release small amount of progesterone (but it is almost hundred times lower than during menstruation).
Drop in estradiol levels in menopause is one of causes of dry skin and wrinkles in women. That's why estrogen creams, sometimes with progesterone, are used for skin nourishment after menopause.
Menopause is the missing of 12 continuous menstrual cycles.
Symptoms of menopause include:
Heavy, irregular bleeding lasting over 10 days (in 90% cases); from 30-55 mL to almost 70 mL.
Hot flashes and night sweat (due to temperature changes in body).
Breast tenderness and swelling (though reduce as estrogen levels drop).
Vaginal dryness.
Mood swings, irritability and anxiety.
Dry skin and changes in oiliness.
Difficulty in sleeping.
Menopause symptoms in certain women might be difficult to show up, especially those with abnormal menstrual cycles in their prime & have other health problems such as:
PCOS (polycystic ovary syndrome).
Uterine or ovarian problems.
Chronically ill.
Engage in heavy aerobic exercises.
Undergone a hysterectomy.
Testosterone is called the male sex hormone (androgen), but it is equally important for women. Both ovaries and adrenal glands produce androgens in women.
Average testosterone levels in females are around ten-times lower than in men.
The chart below shows one of our lab's reference ranges for free testosterone levels in women and men. Because these ranges depend on a given lab, one should always review their results along with the reference ranges.
Figure 6. Reference ranges for normal free testosterone levels in women and men from one of the labs. These ranges are plotted based on a saliva sample, which is an easy, simple way to reliably collect the sample from the comfort of your home. To measure total testosterone, a blood sample is required since the protein that binds testosterone (SHBG) can't be measured with saliva.
There is little change in testosterone levels during the menstrual cycle, with a potentially small uptick around ovulation.
Comparison of several studies had mixed results and weren't able to conclude if there is a clear pattern of change in average testosterone levels between the follicle and luteal phases.
In general, for both men and women, normal testosterone levels start declining in their twenties.
Menopause leads to a decline in many hormones in the ovaries.
Thus, testosterone produced by ovaries declines at perimenopause (i.e., at the early stage of menopause). In parallel, levels from adrenal glands also decline slowly with age. Therefore, one should expect low testosterone levels in women after menopause.
But that's not what you might see in a menopause hormone test.
Although total testosterone levels continuously fall with age, free testosterone levels may be elevated in women after menopause.
Most of the testosterone is not in free form, and binds to a protein called SHBG (sex hormone binding globulin). Therefore SHBG levels also affect the bioavailable testosterone in the blood.
In fact, SHBG levels decline after menopause which leads to an increase in the free form. This can be one of the reasons for high testosterone levels in women after menopause.
Hormone imbalance occurs when the body is producing too much or too little than desired. The reasons include:
Natural changes with age, menstruation, pregnancy, menopause, etc.
Direct exposure to chemicals such as pesticides, herbicides, insecticides, plastics.
Plastics, environmental toxins, and other household items that contain industrial synthetic compounds that behave as hormones; examples include phthalates, PCB (polychlorinated biphenyl), BPA (bisphenol A), etc.
Chemicals in foods such as those used in raising animals and plants (e.g., growth hormones, antibiotics, supplements).
Everyday products such as creams and sprays.
Medications and supplements.
Health conditions such as chronic stress, obesity, etc.
Health problems such as diabetes, tumors in the glands, cancer, etc.
Lifestyle decisions such as exercise, consumption of processed food and sugary, caffeinated drinks, smoking, alcohol, recreational drugs, etc.
Possible outcomes of hormone imbalance in women are:
High estradiol levels: Early menarche (early onset of puberty), premenstrual symptoms, irregular menstrual bleeding, uterine fibroids, endometriosis, muscular cramps, painful, heavy bleeding, breast cancer, and fertility problems, PCOS.
Sleep disorder and insomnia.
Mood swings and mental health issues.
Infertility and reproductive health concerns.
Sexual problems including low libido and erectile dysfunction in men.
Fibroids and endometriosis (growth of uterus lining outside).
Vaginal dryness and painful intercourse.
Order an at-home women's health test.
Order an at-home women's health test.
All About Cortisol - a review of the stress hormone.
All About Thyroid - a review of the thyroid hormones.
All About Vitamin D – review of symptoms and impact.
Testosterone and Aging - how testosterone changes with age.
Hormones for Optimal Health – learn about some of the key hormones & their role.
Hormone Testing - Role of FSH and LH Levels – learn how FSH and LH affect pregnancy and menopause.
Sleep and the Role of Melatonin and Cortisol Levels – short summary of sleep problems and two key hormones.
Saliva Testing - Advantages and Challenges – review of science on saliva based testing.
Cortisol: Risk Factors – review of key risk factors for the stress hormones.
Morning Cortisol Levels – Why levels and collection times are so important.
