Oestrogen is one of the main female sex hormones that guides puberty, menstrual cycles, fertility, pregnancy, and long-term health. Your body makes most oestrogen in the ovaries, and smaller amounts in the adrenal glands and fat tissue. Levels shift across the month and across life, so it helps to know what is typical, what might feel off, and when to seek care. This article explains what oestrogen does, how estradiol, estrone, and estriol change from puberty through menopause, what happens during each phase of the menstrual cycle, and how testing works in Australia. You will also find practical ways to manage symptoms at home, when to book in with a GP or specialist, and how tools like ovulation and pregnancy tests fit into the picture. Information is written for Australian readers and follows local guidance so you can make steady, informed choices.
Quick Answers About Oestrogen Levels
What does oestrogen do?
Oestrogen shapes menstrual cycles and fertility, supports bone strength, brain and mood function, and keeps the vagina and urinary tract healthy. It also affects cholesterol handling and blood vessels.
When is oestrogen highest in the cycle?
Estradiol rises through the follicular phase and peaks just before ovulation, then drops, and has a smaller rise in the luteal phase before falling ahead of a period.
How can I tell if my oestrogen is low or high?
Low levels can cause irregular or missed periods, hot flushes, vaginal dryness, low mood, poor sleep, and reduced libido. Higher levels may cause breast tenderness, bloating, headaches, heavier periods, or mood changes. A GP can confirm with history, examination, and blood tests.
What is oestrogen and how it changes across life
Oestrogen is a family of hormones with three main forms. Estradiol is the dominant form in the reproductive years and is produced mostly by the ovaries. Estriol is prominent in pregnancy and is made by the placenta. Estrone becomes the main circulating form after menopause and is formed in fat tissue and the adrenal glands. Although the ovaries are the key source in younger years, the adrenal glands and adipose tissue continue to contribute across life. In some health conditions, the ovaries can produce too little or too much oestrogen, which can affect cycles and overall wellbeing.
During the reproductive years, estradiol coordinates the growth of the uterine lining, supports cervical mucus production, and primes the mid-cycle luteinising hormone surge that triggers ovulation. In pregnancy, estriol helps maintain uterine blood flow and supports the environment for healthy fetal growth. After menopause, the natural fall in ovarian estradiol can lead to hot flushes, night sweats, mood and sleep changes, vaginal dryness, and long-term effects on bone and metabolic health. Not every symptom is due to hormones alone, which is why a clinical review matters.
The heart and blood vessels also respond to oestrogen. Healthy estradiol levels help the lining of blood vessels relax through nitric oxide pathways and may reduce low-grade inflammation. As levels fall with age, blood pressure and cholesterol patterns can change. Lifestyle steps and medical care can reduce risk across life.
Aging changes in the female reproductive system
Oestrogen across your menstrual cycle
Ovarian estradiol naturally rises and falls during each menstrual cycle. Ranges vary across Australian laboratories and depend on timing, but patterns are consistent. During menstruation, estradiol is generally lower while the uterine lining sheds. Through the follicular phase, growing follicles make more estradiol as one dominant follicle matures. This rise thickens the lining and prepares the cervix for sperm transport. A peak in estradiol signals the brain to release luteinising hormone, which triggers ovulation about one day later. After ovulation, estradiol and progesterone work together to support the luteal phase. If pregnancy does not occur, both hormones fall and a period starts.
Approximate estradiol levels by phase include below 50 pg per mL during menstruation, then a rise from about 19 pg per mL to 140 pg per mL through the follicular phase, a mid-cycle peak near 400 pg per mL, and a luteal phase level around 160 pg per mL before falling again. Australian labs often report pmol per L. These numbers are guides only and should be interpreted with cycle day and clinical context.
In pregnancy, the placenta becomes the main source of oestrogen. Levels remain high and stable across trimesters, which supports uterine blood flow and helps explain nausea, breast tenderness, and fatigue in early pregnancy.
Causes and symptoms of low or high oestrogen
Oestrogen levels can change with age, cycle timing, weight changes, high training loads, stress, thyroid or pituitary disorders, polycystic ovary syndrome, perimenopause and menopause, pregnancy and breastfeeding, some medications, and conditions that affect ovarian function. Smoking, heavy alcohol use, and very low body fat can also alter levels. Sometimes levels appear normal on a single blood test even when symptoms suggest imbalance, which is why timing and repeat testing may be needed.
Low oestrogen can feel different for each person. You might notice irregular or missed periods, hot flushes, night sweats, vaginal dryness or discomfort, reduced libido, low mood, anxiety, poor sleep, difficulty concentrating, headaches, or joint and muscle aches. Over time, bone strength can be affected. In younger women, low oestrogen and low progesterone can make it harder to conceive.
High oestrogen may show as breast tenderness, fluid retention or bloating, headaches, heavier or longer bleeding, shorter cycles, mood swings, or a sense of being more reactive to stress. Fibroids or endometriosis can flare with oestrogen sensitivity, though other hormones and factors also contribute.
If symptoms are new, severe, or persistent, arrange a GP appointment for assessment and support rather than waiting for them to pass on their own.
How oestrogen imbalance is diagnosed and what the tests involve
Your GP starts with a detailed history and examination. They will ask about cycle length and flow, pregnancy plans, contraception, medications or supplements, weight changes, sleep, training load, hot flushes, vaginal symptoms, headaches, breast changes, and family history. A pregnancy test is usually first if periods are late. Your GP may suggest a symptom diary or cycle tracking to guide timing of tests.
Blood tests often include estradiol, follicle stimulating hormone, luteinising hormone, progesterone, thyroid function, and prolactin. The timing depends on the question. Day two to day four tests can assess ovarian reserve and baseline hormones. Mid cycle testing helps when ovulation timing is unclear. Mid luteal progesterone checks ovulation. If PCOS is suspected, your GP may add androgens and fasting metabolic tests. Pelvic ultrasound may be requested for heavy or irregular bleeding, pain, fibroids, or suspected PCOS.
In pregnancy, oestrogen is not usually tested because management relies on clinical care and ultrasound. In perimenopause and menopause, diagnosis is based on symptoms and age, and a blood test is not always needed. For women over 45 with typical symptoms, guidelines support a clinical diagnosis. If you are under 45, or if periods stop early, blood tests can help assess ovarian function.
Tests are done through accredited Australian pathology labs. With a GP referral, many tests attract a Medicare rebate. Your doctor will explain costs, timing, and any preparation, such as fasting for some metabolic checks. Results are interpreted alongside your symptoms and goals, not in isolation.
Managing oestrogen at home and in everyday life
Simple steps can support steady hormones. Aim for regular meals with plenty of plants, whole grains, lean proteins, and calcium rich foods. Add foods that contain natural phytoestrogens such as soy and linseed if they suit your diet. Keep alcohol low and avoid smoking. Build a mix of aerobic and resistance exercise most days, and include rest. Aim for a steady, healthy weight since both very low and higher body fat can affect cycles and oestrogen production. Prioritise sleep and simple stress management, such as walking, breathing exercises, or short relaxation practices you enjoy.
Vaginal moisturisers and lubricants can ease dryness and discomfort. Cotton underwear and fragrance free laundry products can reduce irritation. Heat packs and gentle movement can help period pain. Track your cycle with a calendar, a basal thermometer, or reliable apps so you can match symptoms to timing. If you are trying to conceive, focus on the window around ovulation.
Medication choices depend on your goals and medical history. The combined oral contraceptive pill or a hormonal IUD can regulate bleeding and reduce period pain. Menopause hormone therapy may ease hot flushes, sleep problems, and vaginal symptoms when used at the right dose for the right person. These treatments have benefits and risks, including effects on breast tissue and clotting risk, so discuss options with your GP or specialist and review them regularly.
Natural supplements are often marketed for hormones, but quality and evidence vary. Speak with your GP or pharmacist before starting anything new, especially if you take other medicines.
When to see a GP or specialist in Australia and how tests at home fit in
Book a GP appointment if your periods stop for three months and you are not pregnant, if cycles are shorter than 21 days or longer than 35 days, if bleeding is very heavy or very painful, if you have signs of anaemia such as fatigue or breathlessness, or if pelvic pain is new. Seek care if menopausal symptoms affect sleep, mood, work, sex, or daily life. If you are under 35 and have been trying for a baby for 12 months, or over 35 for six months, ask about a fertility assessment. You may be referred to a gynaecologist, endocrinologist, or fertility specialist depending on findings.
Ovulation predictor kits measure luteinising hormone in urine, which rises after estradiol peaks, and can help time sex or insemination during the fertile window. Most home ovulation tests track luteinising hormone only. Some digital systems also measure a urinary oestrogen metabolite. Pregnancy tests measure human chorionic gonadotropin and confirm pregnancy after implantation. These tools do not diagnose oestrogen imbalance, but they can add useful timing information when paired with cycle tracking and medical care as needed.
If you are unsure where to start, your GP, Healthdirect, state family planning services, and organisations such as Jean Hailes offer reliable, Australian specific guidance.
Frequently Asked Questions About Oestrogen Levels Australia
Do I need a blood test to diagnose menopause?
For women over 45 with typical symptoms and changing cycles, doctors in Australia often make a clinical diagnosis without a blood test. Testing may be used if you are younger, have early or premature menopause, or if symptoms or contraception make the picture unclear.
Can I test oestrogen at home?
Home kits do not measure estradiol in a reliable way for diagnosis. Some digital fertility monitors measure a urinary oestrogen metabolite along with luteinising hormone. For medical decisions, blood tests arranged by your GP provide the most useful information.
What is a normal estradiol level?
Normal ranges vary by lab and cycle day. Levels are lower during a period, rise through the follicular phase, peak just before ovulation, then dip and rise modestly in the luteal phase. Your GP will interpret results with timing and symptoms in mind.
Does the pill change oestrogen levels?
The combined pill contains synthetic hormones that suppress ovulation. Blood estradiol is usually lower on the pill, and bleeding patterns are controlled by the pill schedule. This is expected and not a sign of poor health.
Can plant oestrogens help menopausal symptoms?
Phytoestrogens in soy and linseed may ease mild symptoms for some women. Effects are variable and smaller than prescribed therapy. If symptoms are moderate or severe, speak with your GP about options, including menopause hormone therapy.
Does oestrogen affect heart health?
Oestrogen supports healthy blood vessel function and cholesterol handling during reproductive years. As levels fall with age, cardiovascular risk can rise. Lifestyle changes and regular checks with your GP help manage long term risk.
A final word on oestrogen, testing, and next steps
Understanding oestrogen gives you a clearer way to read your cycle, plan pregnancy, and care for health across life. If you are tracking fertility, focus on the days around the luteinising hormone surge and confirm timing with a reliable ovulation test. If your period is late, a sensitive home pregnancy test can guide your next steps, followed by GP care. If you are navigating perimenopause or menopause, small daily habits and the right medical plan can ease hot flushes, sleep issues, and vaginal symptoms. If periods are erratic, heavy, painful, or absent, or if symptoms affect your work, relationships, or confidence, book a GP review in Australia and ask about blood tests, ultrasound, or a referral where needed. For day to day support, cycle tracking tools such as ovulation tests, pregnancy tests, and basal thermometers can add useful timing information while you work with your doctor on a plan that fits your goals.
References
https://www.healthdirect.gov.au/oestrogen
https://www.healthdirect.gov.au/menopause
https://www.healthdirect.gov.au/oestradiol-blood-test
https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/menopause
https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/hormone-replacement-therapy-hrt
https://www.jeanhailes.org.au/health-a-z/menopause
https://www.jeanhailes.org.au/health-a-z/menopause/menopause-hormone-therapy-mht
https://www.racgp.org.au/afp/2012/july/abnormal-vaginal-bleeding
https://www.fpnsw.org.au/health-information/menopause
https://www.health.qld.gov.au/news-events/news/menopause-symptoms-hormone-therapy
Evan Kurzyp
Evan is the founder of Fertility2Family and is passionate about fertility education & providing affordable products to help people in their fertility journey. Evan is a qualified Registered Nurse and has expertise in guiding & managing patients through their fertility journeys.
