Oestrogen—the matriarch of female sex hormones. But what exactly does it do in the body, what’s its role in the menstrual cycle and what are the symptoms to look for if your oestrogen has become imbalanced? Read on to find out.  Quick facts: What is oestrogen? Oestrogen is an important reproductive hormone in people of all sexes. It’s generally known as the ‘female’ sex hormone, because of its role in the development of the female reproductive system and regulation of the menstrual cycle.  Oestrogen works to enable ovulation and produce female sex characteristics. When we have healthy levels of oestrogen, it can help us to feel feisty, frisky and fabulous. Whilst it’s true that oestrogen plays a bigger role in those assigned-female-at-birth, everybody produces oestrogen, regardless of sex. In those assigned-female-at-birth, oestrogen is produced mainly in ovaries and depends on other reproductive hormones including follicle stimulating hormone (FSH), luteinising hormone (LH) and testosterone for both its production and regulation. Like all of our hormones, our oestrogen levels can sometimes become off-balanced—with many different lifestyle and genetic factors impacting its production and regulation throughout the body. Types of oestrogen? There are three different types of oestrogen, also sometimes spelt estrogen (the American spelling). What does oestrogen do? Oestrogen wears many hats—it helps to regulate our menstrual cycles, triggers the development of secondary sex characteristics like breasts and pubic hair and helps to maintain things like our skin’s moisture, our mood and even our bone and heart health. Let’s take a look at these in more detail: What is oestrogen’s role in the menstrual cycle? Like all of our menstrual cycle hormones, our oestrogen levels during the menstrual cycle fluctuate.  During the first part of our menstrual cycles, the follicular phase, which lasts from day 1 of our periods until ovulation (when we release a mature egg), our oestrogen levels start off low but steadily increase. In this phase, our eggs are maturing in preparation for ovulation.  Our eggs mature in our ovaries, in little sacs called follicles. These follicles make oestrogen, so whilst your eggs are maturing, your follicles steadily release this oestrogen—and it rises until it reaches a peak, just before we ovulate. Because of oestrogen’s feel-good factors, just before and during ovulation is the time of the month when we’ll be killing it, feeling our most fierce and fabulous. This is the time to book that big presentation at work, go on that first date or really push it in your gym session. This peak in oestrogen causes a surge in LH, which triggers the release of a mature egg from one of our ovaries during ovulation. After ovulation, oestrogen levels gradually drop and despite a small second wind around a week later, they continue to level off throughout the second stage of our menstrual cycles—the luteal phase. At the end of our cycles, if the ovulated egg has not met a sperm and been fertilised, all of our menstrual cycle hormones, including oestrogen, drop off to their baseline levels—triggering our periods. If our oestrogen levels get off balance, it can disrupt the balance of our other menstrual cycle hormones—potentially impacting ovulation. No ovulation = no pregnancy. So if you’re trying to get pregnant, testing your hormone levels is really important for understanding your ovulation and general menstrual cycle health. What affects oestrogen levels? As well as fluctuating naturally month to month, lots of other lifestyle, genetic and medical conditions can affect our oestrogen levels, including: Does oestrogen decline with age? Thanks to our wonderful ‘biological clocks’, as we age, our oestrogen levels gradually decline. This is because our number of egg cells decreases as we age and as a result, our follicles stop growing and producing as much oestradiol (E2). After menopause (when our periods stop completely), our E2 levels completely drop off, which is what causes the common low oestrogen menopausal symptoms like hot flushes, dry skin and mood swings. During perimenopause (the lead up to menopause), E2 levels fluctuate up and down which can also cause menopausal symptoms. Declining oestrogen levels has whole-body knock-on effects, but luckily these days hormone replacement therapy (HRT) can be a great option to relieve symptoms for many people during perimenopause and postmenopause. How do I know if my oestrogen levels are normal? Because our oestrogen levels fluctuate during our cycles, as we age, and are dependent on whether we’re taking hormonal birth control or not, our ‘normal’ level is constantly changing.  Like all of our hormones, our oestrogen is super sensitive and can easily get off balance. Oestrogen imbalances can cause a whole host of symptoms and can be caused by both lifestyle and genetic factors. Symptoms of high oestrogen levels Oestrogen dominance is a phrase that has been used to describe a phenomenon when oestrogen levels are too high in relation to the other sex hormones in your body.  Although it’s not a clinically recognised term, being more sensitive or having excess oestrogen is known to cause symptoms like irregular periods, abnormal vaginal bleeding, bloating, swollen or tender breasts and weight gain. Some causes of high oestrogen levels include underlying health conditions, genetic factors, dietary and lifestyle factors and environmental pollutants. Symptoms of low oestrogen levels On the flip side, when oestrogen levels are too low we can experience irregular periods, fertility difficulties, reduced bone density, vaginal dryness, hot flashes and dry skin—to name a few. Having very low oestrogen levels can be caused by your ovaries not working properly, which occurs in menopause or primary ovarian insufficiency (POI). However, underlying health conditions like pituitary gland disorders, as well as having very low levels of body fat, a high caffeine intake, smoking and excessive exercise can also result in lower oestrogen levels. Luckily, testing our E2 levels with a hormone test can help us to decipher if our oestrogen levels are within the normal range for us. Oestrogen FAQs Where can I get an oestrogen blood test? You’ve landed in the right place. With a Hertility Hormone and Fertility test […]