Oestrogen is one of the two main female sex hormones that control your reproductive health and fertility. Paying attention to this hormone’s levels is important to maintaining good reproductive health. Apart from being involved in your reproductive system, oestrogen plays several other roles, from controlling your lipid metabolism to bone health. Your body must maintain the correct levels of this important hormone. Too low or too high oestrogen levels can affect your reproductive system and overall health. This article intends to explain oestrogen’s role in your body and how its levels fluctuate. We will also discuss normal oestrogen levels and how to tell if you have an imbalance in your body’s important hormone.

What is Oestrogen?

Oestrogen is a steroidal hormone secreted by the ovaries, which acts as one of the primary sex hormones for females. It directly impacts your reproductive health, fertility, and other bodily functions. Although the ovaries are major oestrogen-secreting organs, the adrenal glands and fatty tissue produce a small amount of the hormone. In certain medical conditions, ovaries tend to have too little or too much oestrogen, leading to several health issues.

Estradiol, Estrone, and Estriol Across Life Stages

Understanding each oestrogen’s role clarifies how hormonal changes affect a woman’s health throughout her life.

During the reproductive years, estradiol dominates. It regulates the menstrual cycle, supports ovulation and fertility, and ensures the proper development of reproductive tissues.

During pregnancy, estriol takes precedence. Produced mainly by the placenta, it supports a healthy gestational environment by modulating immune responses and maintaining the uterus for fetal growth.

After menopause, ovarian oestrogen production drops significantly. Estrone becomes the primary circulating form, generated mainly through conversion in adipose tissue and the adrenal glands. It sustains baseline oestrogenic activity despite reduced ovarian output.

Leading endocrinology experts and peer-reviewed research highlight that recognising these differences is essential for understanding how hormonal changes affect health across life stages. This clarity empowers individuals to make informed decisions and seek appropriate clinical advice based on their unique hormonal profiles.

What does Oestrogen do?

Oestrogen is essential not only for reproductive functions but also for maintaining cardiovascular health. Research shows that oestrogen improves endothelial function by stimulating nitric oxide production, a molecule crucial for blood vessel relaxation and effective vasodilation. This nitric oxide pathway ensures consistent blood flow and optimal blood pressure, supporting overall heart function.

Beyond regulating vascular tone, oestrogen offers significant anti-inflammatory benefits in the circulatory system. By reducing inflammatory responses, it prevents arterial stiffness and slows the progression of atherosclerosis. Dr Elizabeth Barrett-Connor, a leading cardiovascular endocrinologist, states, “Oestrogen’s influence on vascular inflammation and nitric oxide production is a critical component of its cardioprotective benefits.”

These cardiovascular benefits are strongest during the reproductive years. As natural oestrogen levels decline with age—especially during and after menopause—the loss of these protective effects increases the risk of conditions like hypertension and atherosclerotic disease. Recognising these changes, it is essential to monitor hormonal balance and consult healthcare professionals to develop strategies that manage cardiovascular risk throughout different life stages.

Oestrogen levels during your menstrual cycle

Menstruation

Oestrogen remains below 50 pg/ml (≈184 pmol/L) while the uterine lining sheds.

Follicular Phase

Levels rise from about 19 pg/ml (≈70 pmol/L) to nearly 140 pg/ml (≈514 pmol/L) as ovarian follicles mature.

Ovulatory Phase

Oestrogen peaks at around 400–410 pg/ml (≈1468–1505 pmol/L), indicating peak fertility.

Luteal Phase

After ovulation, levels increase to approximately 160 pg/ml (≈587 pmol/L) before dropping to about 19 pg/ml (≈70 pmol/L) by cycle’s end.

Oestrogen levels in Menopause

After menopause, ovarian oestrogen production ceases, and the hormone is primarily derived from the adrenal glands and adipose tissue. Typically, post-menopausal estradiol levels can be as low as 35 pg/ml (approximately 128 pmol/L), with a normal range falling between 10 pg/ml (about 37 pmol/L) and 50 pg/ml (roughly 184 pmol/L).

Pregnancy

Pregnancy

During pregnancy, the placenta becomes the main source of oestrogen, creating a stable hormonal environment. This rise in oestrogen enhances blood flow to the uterus by promoting vasodilatory agents that relax uterine muscles and dilate blood vessels, ensuring the fetus receives adequate oxygen and nutrients.

Unlike non-pregnant women, where oestrogen levels fluctuate with the menstrual cycle, pregnancy maintains high placental oestrogen. This steady hormone level improves uterine blood flow and is linked to early pregnancy symptoms like nausea, breast tenderness, and fatigue. These symptoms reflect the body’s natural adjustment to the increased demands of supporting both mother and baby.

Understanding these physiological changes highlights the importance of regular prenatal monitoring and personalised care to ensure a healthy pregnancy outcome.

Oestrogen levels in Menopause

After Menopause, no new follicles develop in your ovaries, and they stop producing oestrogen. The body makes several different forms of oestrogen, including estradiol and Estrone, mainly from the adrenal gland and adipose tissue. The decline in oestrogen levels leads to the unpleasant symptoms that many women experience during Menopause, including hormone flashes and low libido. Hormone replacement therapy (HRT) with the right amounts of oestrogen is often used to alleviate the symptoms of Menopause. Your doctor might prescribe your HRT in very small doses until your body is accustomed to the lower oestrogen levels. According to the Woman’s Health Initiative , excessive use of oestrogen replacements during HRT can harm your health. An increased oestrogen level after Menopause might lead to breast cancer and increase your risk of developing a heart condition and stroke. Women who have been diagnosed with osteoporosis are seldom given HRT. The oestrogen levels after Menopause can be as low as 35 pg/ml or more. A range between 10 and 50 pg/ml is considered normal.

What is a low level of oestrogen?

If oestrogen levels are lower than normal, it can make it difficult for you to conceive. It is important to recognise how low oestrogen levels can impact your fertility.

Signs and Symptoms

Fluctuations in oestrogen levels can influence more than reproductive processes; they also affect mental and emotional well-being. Variations in this hormone may disrupt neurotransmitter regulation, leading to mood disturbances such as depression, anxiety, and irritability. These mood changes can become particularly pronounced during the premenstrual phase or the transition into menopause.

Other signs that your oestrogen levels may be lower than optimal include:

• Irregular or missed menstrual cycles
• Persistent low mood or episodes of depression
• Heightened anxiety and irritability
• Increased fatigue and difficulty concentrating
• Sleep disturbances or feelings of restlessness
• Sensitivity to stress and sudden mood swings
• Physical discomfort such as hot flashes, breast tenderness, and muscle aches

If you experience these symptoms, it is important to consult a healthcare professional for a comprehensive evaluation and personalised guidance.

Treatment for Low Oestrogen Levels

Managing low oestrogen begins with a thorough hormonal assessment. After a comprehensive clinical evaluation of your hormonal profile and overall health, a personalised treatment plan is developed. Key strategies include dietary changes—adding natural, phytoestrogen-rich foods—and a structured program of moderate exercise. These interventions are introduced gradually and monitored through regular reassessments, allowing adjustments based on your body’s responses. This holistic approach, supported by current clinical research and endocrinology guidelines, ensures each adjustment promotes balanced hormone regulation safely and effectively.

Long-Term Metabolic and Inflammatory Considerations

While immediate symptoms of oestrogen imbalance are often the main concern, lasting hormone deviations can affect overall health. Persistent imbalance can disrupt metabolism, altering insulin sensitivity and lipid processing. Additionally, chronic low-grade inflammation may increase the risk of type 2 diabetes and other metabolic conditions. These issues emphasise the need for regular hormonal assessments and proactive lifestyle choices. Collaborate with healthcare professionals to develop personalised strategies that maintain balanced oestrogen levels and support long-term wellbeing.

Evan kurzyp

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.