Category: Understanding Your Hormones

Anti-Müllerian Hormone (AMH) is one of the most talked-about fertility hormones, but also one of the most misunderstood. Because AMH is closely linked to your eggs, testing it can offer valuable insight into your ovarian reserve (the number of eggs you have left). But it’s not a fertility “yes or no” test. In this guide, we break down exactly what AMH testing can and can’t tell you about your reproductive health.  Quick facts: What is AMH and why is it so important? Anti-müllerian hormone (AMH) is made by small fluid-filled sacs in the ovaries called follicles, each of which houses an immature egg. Because AMH is made by these follicles, your AMH level gives an indication of how many eggs you may have remaining at a given time. However, this is only one piece of the fertility puzzle. There are a few myths out there about what exactly AMH testing can tell us. In this article, we cover the main things an AMH test can and can’t tell you. Let’s get into it. What can AMH testing tell me? Whether your ovarian reserve is a normal for your age AMH testing will give you insights into whether your ovarian or egg reserve is what is expected with other healthy people in your age group. It helps you understand whether your egg reserve is higher, average, or lower than expected for your age. If you are not using any hormonal contraception, testing other hormones, like follicle-stimulating hormone (FSH) and oestradiol alongside AMH can also help to build a more complete picture of egg reserve. Generally, people with low egg reserves are known to have higher levels of FSH and lower levels of oestradiol. Whether you have polycystic ovaries or polycystic ovary syndrome AMH testing can also be used as an indicator of whether you could have polycystic ovaries (PCO). PCO is a common reproductive health condition affecting around 30% of reproductive-aged people assigned female-at-birth. PCO is benign and does not affect fertility, but it can cause other unwanted symptoms.  People with PCO have a higher-than-expected number of immature follicles in their ovaries. More follicles mean a higher level of AMH in the blood.  Some people with PCO also have the syndrome that can be associated with it polycystic ovary syndrome (PCOS), which often presents as symptoms like irregular periods, acne, hair thinning or loss and high testosterone levels. According to updated guidelines, AMH can now be used as an indicator for polycystic ovaries in place of doing an ultrasound scan for the diagnosis of PCOS. However, at Hertility, we would always recommend getting a pelvic ultrasound scan to further assess your ovarian reserve. During this scan, your ovaries are assessed to determine your antral follicle count (the number of eggs sacs seen within your ovaries) and to confirm the diagnosis. Whether IVF or egg freezing could be right for you In fertility treatment settings, AMH plays an important role in guiding decisions around interventions such as IVF and egg freezing . It is commonly used to estimate how the ovaries may respond to stimulation and to guide medication dosing.  Lower AMH levels are generally associated with retrieving fewer eggs during IVF, while higher levels may indicate a stronger response but also carry a risk of developing a rare but potentially life threatening condition called OHSS (ovarian hyperstimulation syndrome). This makes AMH a valuable tool for planning treatment safely and effectively. Many NHS-funded and private IVF clinics therefore require a minimum AMH level for you to be eligible for a free IVF treatment cycle. The minimum level on the NHS will depend on where in the UK you are currently residing. Whether you may be perimenopausal or menopausal or have POI Menopause marks the point at which your periods stop permanently, typically between the ages of 45 and 55, with the average age for menopause in the UK being 51. After menopause, natural conception is no longer possible. It is associated with a very low, or completely depleted, ovarian reserve. Clinically, menopause is usually diagnosed retrospectively, after 12 consecutive months without a period in someone not using hormonal contraception. In individuals under the age of 45, follicle-stimulating hormone (FSH) is more commonly used as a diagnostic marker, as levels tend to rise when ovarian function declines. While AMH is not currently recommended as a standalone test to diagnose menopause, it is well established that AMH levels fall to very low levels as ovarian reserve diminishes. This makes AMH a useful indicator of overall ovarian activity. Declining or very low AMH levels can suggest that you are approaching menopause, although it cannot predict the exact timing. In younger individuals, particularly those under 40, significantly low AMH levels may raise suspicion of premature ovarian insufficiency (POI), a condition in which the ovaries stop functioning earlier than expected. What can’t AMH testing tell me? While AMH testing is a useful tool for understanding your ovarian reserve, it only represents one part of your overall fertility picture. There are several important limitations to be aware of, and understanding these can help you interpret your results more accurately and avoid common misconceptions. It can’t determine your egg quality One of the biggest limitations is that AMH cannot tell you anything about your egg quality. Although AMH reflects the number of eggs you may have remaining, it does not provide any insight into how healthy those eggs are. Egg quality is one of the most important factors influencing fertility and pregnancy outcomes, and it is largely driven by age and genetics. At present, there is no reliable test to measure egg quality directly, except through assessing embryos during IVF treatment. It can’t determine your exact egg quantity AMH also cannot determine your exact number of eggs. While it gives an indication of the size of your ovarian reserve, it is not a precise measurement. This is because AMH is made by ovarian follicles, and each follicle can release different amounts of the hormone depending on its size and […]

Anti-Mullerian Hormone (AMH) is one of the most talked-about markers in fertility and reproductive health. It is often described as a measure of ovarian reserve, which means the number of eggs remaining in the ovaries. While much of the conversation focuses on low AMH, receiving a high result can raise its own set of questions. Does high AMH mean you are more fertile? Does it mean you have polycystic ovaries? Could it be linked to PMOS ( formerly known as PCOS)? And does having high AMH mean it will be easier to get pregnant? The answer is more nuanced than a simple yes or no. High AMH levels usually suggest that your ovaries contain a higher-than-expected number of small follicles for your age. This may be linked to polycystic ovaries, PMOS or natural variation. However, AMH does not measure egg quality, does not confirm whether you are ovulating regularly, and does not predict whether you will conceive naturally. In this guide, we explain what high AMH levels mean for fertility, what causes it, how it relates to PCO and PMOS, what it can mean for IVF, and how Hertility interprets your AMH result as part of your wider hormone health. If you haven’t yet tested your AMH, our Advanced At-Home Hormone & Fertility Test can measure AMH alongside up to nine other key hormones, giving you a personalised, clinically meaningful picture of your reproductive health. Quick Facts What is AMH? Anti-Müllerian hormone (AMH)  is a hormone made by small fluid-filled sacs in the ovaries called follicles, each of which contains an immature egg. Because AMH is made by these follicles, it gives an indication of how many eggs you have remaining at a given time. This is known as your ovarian reserve. Ovarian reserve refers to egg quantity, not egg quality. This distinction is important. AMH can help estimate the number of eggs remaining, but it cannot tell you whether those eggs are genetically healthy, whether they will fertilise, or whether they will develop into a viable pregnancy. Unlike hormones such as FSH, oestradiol, and LH, which fluctuate significantly across the menstrual cycle, AMH remains relatively stable. This means it can usually be measured at any point in the cycle and still provide useful information. However, recent studies have shown that there may be some slight variation in AMH levels across the menstrual cycle, but this variation remains considerably smaller than that seen in other reproductive hormones. As a result it is still considered one of the most stable and reliable markers of ovarian reserve. It is also routinely used when someone is considering undergoing a fertility treatment to estimate how the ovaries are likely to respond to fertility medication, guide medication dosage, and inform treatment planning. For a deeper dive into everything AMH testing can and can’t tell you, including its role in identifying  PMOS and guiding fertility treatment, read our full guide: What Does AMH Testing Tell You? 5 Key Insights About Your Fertility What Does “High AMH” Actually Mean? When we refer to “high AMH,” we mean a result that falls above the expected range for your age group. Because AMH naturally declines as you get older, what counts as “high” is always interpreted relative to age-specific reference ranges, not a single universal cutoff. A high result suggests that your ovaries contain a larger-than-expected number of small follicles for someone your age. In practical terms, this means there is more AMH being made and circulating in the bloodstream. In isolation, this is not harmful, but is a signal worth investigating further, as it is closely associated with certain hormonal and reproductive health conditions. Does High AMH Mean I Am Very Fertile? This is the most common and potentially most consequential misconception about high AMH results. A high result can feel like good news, more eggs must mean better fertility, right? In fact, this is not necessarily true. High AMH levels are not automatically good or bad for fertility. AMH tells you about egg quantity. It does not tell you anything about egg quality, that is, how healthy those eggs are, how likely they are to be fertilised, or how likely they are to develop into a viable embryo. Egg quality is influenced primarily by age and genetics, and there is currently no reliable way to measure it directly outside of assessing embryos created during IVF. Beyond egg quality, fertility depends on many factors that AMH cannot assess at all; whether you are ovulating regularly, the health of your fallopian tubes and uterus, and sperm health. A high result offers no reassurance about any of these. In short: a high AMH result does not predict your ability to conceive naturally, and should not delay seeking help if you have concerns about conceiving. What Causes High AMH Levels? A high AMH result reflects a greater number of small follicles in the ovaries than would be expected for your age. The most common reasons for this include: Unlike low AMH, a high result is not associated with previous surgery, cancer treatment, or lifestyle factors. In the vast majority of cases, the underlying explanation is PCO,  PMOS, or natural variation, and your full hormone panel and clinical history will help clarify which. What conditions can high AMH indicate? Polycystic ovaries (PCO) PCO is a common reproductive health condition affecting around 30% of people with ovaries of reproductive age. It is characterised by a higher-than-expected number of small, immature follicles in the ovaries, which is precisely why AMH levels tend to be elevated in people with PCO. More follicles indicates more AMH being produced. Importantly, PCO on its own is benign. It does not affect fertility and does not cause symptoms in most people. It is often identified incidentally, during an ultrasound, or increasingly, through a high AMH result. <p>Because AMH is so closely associated with follicle count, updated clinical guidelines now allow AMH to be used as an indicator of polycystic ovaries in place of an ultrasound scan for the […]

Whether you’ve just come off the pill, had your implant removed, stopped the contraceptive injection or had your IUD taken out, one of the most common questions is: when should I test my hormones after stopping contraception? You might call it birth control or contraception, either way, the timing of hormone testing depends on the method you used and whether your natural cycle has returned. Some forms of hormonal contraception suppress ovulation and temporarily affect the hormones involved in your menstrual cycle. Test too soon, and your results may not reflect your natural baseline. Test at the right time, and your hormone results can give you a much clearer picture of your reproductive health, ovarian reserve and cycle function. Here’s exactly when to test your hormones after stopping contraception, broken down by type. Quick facts: Why timing matters when testing hormones after contraception Hormonal contraception introduces synthetic hormones into your body. Depending on the type, it may suppress ovulation, change cervical mucus, thin the womb lining or affect the signals between your brain and ovaries. Your cycle needs time to restart This signalling system is called the hypothalamic-pituitary-ovarian axis, or HPO axis. It controls the hormones involved in ovulation and menstrual cycles, including FSH, LH and oestradiol. When you stop hormonal contraception, your body needs time to clear the synthetic hormones. Your natural hormonal rhythm also needs time to restart. Some people get their period back within a few weeks. Others need several months before their cycles become regular again. Testing too soon can affect your results If you test cycling hormones too soon, your results may not show your natural baseline. FSH, LH and oestradiol may still look suppressed. Your cycle may also be too unpredictable to time the test correctly. This can make results harder to interpret. You may see results that look abnormal, even though your body is simply adjusting after contraception. You may also get results that seem reassuring but do not show the full picture. Getting the timing right makes your hormone test more accurate and more useful. How does hormonal contraception affect hormone test results? Different hormones respond to contraception in different ways. You can test some markers while you still use contraception. Others need a natural cycle to return first. Cycling hormones (FSH, LH, oestradiol) FSH, LH and oestradiol are cycling hormones. They rise and fall across the menstrual cycle and are closely linked to ovulation. Hormonal contraception can suppress the brain-ovary signals that control these hormones. This happens most clearly with combined hormonal contraception, such as the combined pill, patch and ring. If you test FSH, LH and oestradiol while using hormonal contraception, the results usually show the effect of contraception. They do not show your natural cycle. This is why Hertility recommends waiting until you have had 3 full cycles before testing these markers. AMH or anti-Müllerian hormone, gives information about ovarian reserve. It is not a cycling hormone. This means you can test AMH at any point in your cycle, including while you use hormonal contraception. However, research suggests hormonal contraception may lower AMH in people currently on it, with the effect more pronounced in long-term users. Importantly, AMH levels appear to rebound to true baseline within a few months of stopping. This means an AMH result on contraception can still be useful, but testing or retesting after 3 full cycles off hormonal contraception can give a more accurate baseline. Androgens (testosterone and DHEAS) Hertility can test androgens, including testosterone and DHEAS, while you use hormonal contraception. However, your results need careful interpretation. The combined pill can increase SHBG, or sex hormone-binding globulin. SHBG binds to testosterone in the bloodstream. This can reduce the amount of free, active testosterone available to the body. Hertility always interprets androgen results in context, rather than looking at one hormone on its own. SHBG (sex hormone-binding globulin) The combined pill substantially raises SHBG, which affects the interpretation of any androgen and oestrogen results. SHBG can remain elevated for months after stopping the pill in some people, which is another reason retesting after a full 3 cycles gives a clearer picture. Thyroid hormones (TSH, Free T4) Hormonal contraception does not usually suppress thyroid hormones. You can usually test TSH and Free T4 whether you are on or off contraception. Prolactin Most forms of hormonal contraception do not meaningfully affect prolactin. You can test prolactin at any point. When to test your hormones after stopping the combined pill Recommended wait before testing hormones: 3 cycles after stopping The combined pill contains synthetic oestrogen and progestogen. It works mainly by stopping ovulation, which means it suppresses the natural rise and fall of cycling hormones such as FSH, LH and oestradiol. For most people, natural hormone production begins to resume within a few weeks of stopping, but cycles can take up to 3 months to fully re-establish their rhythm. For the most accurate results, we recommend waiting 3 months after your last pill before testing cycling hormones (FSH, LH, oestradiol). Can AMH be tested after stopping the pill? AMH can be tested at any point, including while you are still on the pill. However, because AMH may be mildly suppressed during hormonal contraception use, testing after 3 full cycles off the pill may give the clearest baseline. If you test AMH while on the pill, the result can still provide useful information about ovarian reserve, but it should be interpreted in context. When to test your hormones after stopping the progestogen-only pill (mini pill) Recommended wait before testing hormones:  3 cycles after stopping The progestogen-only pill, often called the mini pill, contains progestogen rather than oestrogen. It mainly works by thickening cervical mucus, making it harder for sperm to reach an egg. Some types can also suppress ovulation. Because the mini pill may still affect ovulation and cycle regularity, At Hertility, we recommend waiting until you have had 3 full cycles before testing your hormones. This helps ensure your hormone results reflect your natural baseline rather than a cycle that […]

You’ve just received your hormone test results. There are numbers, units, and a column of figures labelled ” hormone reference range” and it’s not immediately obvious what any of it means, or whether you should be worried. You’re not alone. Hormone reference ranges are one of the most misunderstood parts of any blood test result. At Hertility, we interpret your hormone results in clinical context, not just against a number. This guide explains what reference ranges actually are, why they vary, and how to read your results properly. Quick summary What is a hormone reference range? When you receive hormone test results, each value is accompanied by a reference range, a set of numbers that tells you where your result sits relative to a defined population.  The first step in understanding where a reference range comes from is to remember that we expect different things from different groups of people. This can be age-related or gender-related, but can also be lifestyle-related. In actual fact, the ideal ranges are usually pretty broad and rarely take important factors such as ethnicity into account. They are usually defined by the population to which the range will apply (in this case women), but also their age. A large number of individuals from a group who are thought to represent a “normal” population, will be tested for a particular laboratory test. The reference range is then derived mathematically by taking the average value for the group and allowing for natural variation around that value (plus or minus 2 standard deviations from the average). In this way, ranges quoted by labs will represent the values found in 95% of individuals in the chosen ‘reference’ group. In other words, even in a “normal” population, a test result will lie outside the reference range in 5% of cases (1 in 20).  This is precisely why the term “reference range” is preferred over “normal range” in clinical medicine. A result outside the range is not automatically abnormal. A result inside the range is not automatically healthy. The range is a reference point, a tool to aid interpretation, not a binary verdict on your health. Why do hormone reference ranges vary between labs? One of the most confusing aspects of hormone testing is that you can test at two different labs and receive two different results, and both can be correct. This happens for several reasons. Lab environment and equipment. Every laboratory uses precisely calibrated equipment and specific reagents (the chemical substances used to detect hormone levels in a blood sample). Minor differences between labs like temperature, supplier of testing materials, calibration protocols, mean that the same sample can produce slightly different numerical results when analysed in different settings. Neither lab is producing an incorrect result. They are simply measuring with different tools, against different benchmarks. Different reference populations. Each lab establishes its reference range by testing its own reference population. If Lab A and Lab B each test a group of healthy women but recruit from different populations, ages, or regions, their resulting ranges may differ, even if the underlying biology is identical. What this means in practice. If you test at one lab and retest a month later at a different lab, a change in your result may reflect the different reference populations of each lab rather than a genuine change in your hormone levels. This is why, whenever possible, it is best to retest at the same lab  and why any result should always be interpreted against the reference range of the specific lab that analysed your sample, not a generic “normal” value found online. Type of sample: Reference ranges are also different depending on the type of sample used to measure a hormone. Take oestrogen as an example. Oestrogen can be measured in blood, saliva, or urine, but the concentration of oestrogen differs significantly between each of these, and so the reference ranges are different too. This is relevant if you ever compare results from different types of tests. A blood oestrogen result and a urine oestrogen result cannot be directly compared, even if they are measuring the same hormone. The numbers will look different, the reference ranges will be different, and the clinical interpretation will differ accordingly. How hormone reference ranges are categorised by age, sex, and cycle phase Because different groups of people have different hormone levels for entirely normal physiological reasons, reference ranges are not one-size-fits-all. They are adjusted for the characteristics of the population being assessed. By sex Testosterone is a clear example. Men have significantly higher testosterone levels than women, so separate reference ranges exist for each sex. Applying a male testosterone reference range to a female result or vice versa  would make most healthy women appear deficient. By age Many reproductive hormones change significantly across a woman’s lifespan. AMH (anti-Müllerian hormone), which reflects ovarian reserve, naturally declines with age. It would be clinically meaningless to compare a 22-year-old’s AMH to a 42-year-old’s using the same reference range, the 22-year-old would almost always appear to have “better” results simply because of age, not because of any meaningful difference in health status. At Hertility, we use age-stratified reference ranges for AMH and other hormones that change across the reproductive lifespan. This means your result is compared to the expected range for people your age, giving you a more accurate and clinically meaningful interpretation. By cycle phase Cycling hormones like FSH, LH, oestradiol, and progesterone fluctuate significantly throughout the menstrual cycle. Their reference ranges are therefore tied to a specific phase of the cycle. FSH, LH and oestradiol, for example, are typically measured on day 2 or 3 of the menstrual cycle, because the reference ranges for these hormones are calculated on day 3 of a healthy population’s cycle. Testing FSH on day 14 (mid-cycle, around ovulation) and comparing it against a day 3 reference range would produce a meaningless result because LH surges dramatically at ovulation, and FSH also rises. The timing of the test and the timing of the reference […]

Anti-Mullerian Hormone (AMH) is one of the most talked-about markers in reproductive health, providing an insight into your hormonal health and ovarian reserve. But receiving a “low” AMH result can feel alarming, especially when you’re not sure what it actually means. The good news is that a low AMH is not a confirmation that you cannot conceive naturally. In this article, we explore what it means to have a low or out-of-range AMH result, what causes it, and what your options are; whether you’re trying to conceive now, or simply planning for the future. If you haven’t yet tested your AMH, our Advanced At-Home Hormone & Fertility Test can measure AMH alongside up to nine other key hormones, giving you a personalised, clinically meaningful picture of your reproductive health. Quick Facts: A low AMH result indicates a lower-than-expected ovarian reserve for your age, but does not mean you cannot conceive naturally AMH measures egg quantity only, it tells you nothing about egg quality, which is one of the most important factors in conception AMH naturally declines throughout life; a low result does not mean you have done anything to cause it. Certain factors, including hormonal contraception and some medical conditions can temporarily affect AMH levels. Low AMH may have implications for IVF planning and NHS eligibility, but a low result does not close the door on treatment Your AMH result should never be interpreted in isolation, it only makes sense alongside your age, other hormones, and clinical history What is AMH and what does it measure? Anti-Müllerian hormone (AMH)  is a hormone made by small fluid-filled sacs in the ovaries called follicles, each of which contains an immature egg. Because AMH is made by these follicles, your AMH level gives an indication of how many eggs you have remaining at a given time. This is known as your ovarian reserve. Unlike hormones such as FSH, oestradiol, and LH, which fluctuate significantly across the menstrual cycle, AMH remains relatively stable. This stability is one of the key reasons it became widely adopted in reproductive medicine: it can be measured on any day of your cycle and still give a meaningful result. It is worth noting, however, that more recent studies have shown that there may be some slight variation in AMH levels across the menstrual cycle, but this variation remains considerably smaller than that seen in other reproductive hormones. As a result AMH is still considered one of the most stable and reliable markers of ovarian reserve. AMH is now routinely used when someone is considering undergoing a fertility treatment to estimate how the ovaries are likely to respond to stimulation, guide medication dosage, and determine eligibility for treatment. For a deeper dive into everything AMH testing can and can’t tell you, including its role in identifying PCOS and guiding fertility treatment, read our full guide: What Does AMH Testing Tell You? 5 Key Insights About Your Fertility What Does “Low AMH” Actually Mean? When we refer to “low AMH,” we mean a result that falls below the expected range for your age group. Because AMH naturally declines as you get older, what counts as “low” is always interpreted relative to age-specific reference ranges, not a single universal cutoff. A low AMH result can suggest that your ovarian reserve may be lower than expected for someone your age. This is sometimes referred to as having a Diminished Ovarian Reserve (DOR). However, it is important to emphasise that a lower ovarian reserve does not automatically mean reduced fertility or an inability to conceive naturally. The most important thing to understand: AMH measures quantity, not quality This distinction is worth repeating, because it is the most common source of confusion and unnecessary distress after receiving a low AMH result. AMH tells you about egg quantity. It does not tell you anything about egg quality. Egg quality i.e. how healthy eggs are, how likely they are to be fertilised, and how likely they are to develop into a viable embryo is influenced primarily by age and genetics. Currently there is no reliable way to measure it directly outside of accessing embryos created during IVF. This matters enormously in practice. Research consistently shows that AMH levels alone are not strongly predictive of natural pregnancy rates. People with low AMH conceive naturally every day. Conversely, a normal or high AMH result does not guarantee fertility. Fertility is shaped by many factors: ovulation, sperm health, Fallopian tube function, uterine health, and overall wellbeing. In short: a low AMH result is not a diagnosis of infertility. Hertility’s own research found no significant association between low AMH and risk of miscarriage or recurrent pregnancy loss, an important finding that further underscores the limitations of AMH as a standalone predictor of pregnancy outcomes. What Causes Low AMH? In most cases, there is no single identifiable “cause” of a low AMH level in the way we typically think about causes of illness. It is important to know that if you have received a low AMH result, nothing you’ve done has caused this. AMH levels follow a natural trajectory across the reproductive lifespan; it peaks in the early-to-mid twenties, and then gradually declines toward menopause. This decline is a normal part of reproductive ageing, and the rate at which it happens varies between individuals, largely due to genetics. Some factors that may be associated with lower AMH levels include: Age – the most significant driver of declining AMH Genetics – family history can influence the rate of ovarian ageing Previous ovarian surgery – procedures to remove ovarian cysts or tissue (for example endometriosis) may reduce ovarian reserve Certain autoimmune conditions – which can affect ovarian function, for example Hashimoto’s disease, rheumatoid arthritis, and Addison’s disease. Cancer treatment – some types of chemotherapy and radiotherapy are referred to as gonadotoxic (i.e. toxic to the gonads such as the ovary) which can impact the ovaries Hormonal contraception – can cause a temporary, reversible reduction in AMH levels, typically by 15% to 30% and […]

If you’ve ever been told to get bloods done on day 3 and wondered why that specific day matters, or felt frustrated trying to time a test around an unpredictable cycle, this guide is for you. We’re going to explain not just when to test, but why the timing matters at a biological level, what each hormone is actually measuring, and what to do when life doesn’t cooperate with your cycle. First: What does “day 3 of your cycle” mean? Day 1 of your cycle is the first day of your period, this means full menstrual flow, not spotting. If you see light spotting on Monday and Tuesday but don’t experience a proper flow until Wednesday, Wednesday is your day 1. Count forward from there: day 3 is the third day of your period (in this scenario that would be Friday). If your period is less than 3 days, day 3 is the third day after your period starts.  This matters because starting the count from spotting rather than full flow is one of the most common reasons people test at the wrong time. How does the menstrual cycle affect hormone levels? To understand why day 3 matters, it helps to have a basic picture of what’s happening in your body across the menstrual cycle. Your menstrual cycle is divided into two main phases separated by ovulation. The follicular phase always begins on day 1 of the menstrual cycle and ends with ovulation. In a 28-day cycle, the follicular phase extends from day 1 to approximately day 14. The luteal phase then follows ovulation and typically lasts 14 days, ending when your next period begins. The follicular phase is a period of rapid hormonal change, making it significant for hormone testing. When the previous menstrual cycle completes, levels of oestrogen and progesterone decrease. This triggers the release of follicle-stimulating hormone (FSH) into circulation.  Therefore, the days right around day 3 are when your body’s hormone system essentially resets and returns to its baseline. This is precisely why it’s the ideal time to take a snapshot of your reproductive hormones. Which hormones can be tested on day 3, and what does each one tell us? At Hertility, we test a broader panel than many providers. Here’s a detailed breakdown of each hormone in our Advanced At-Home Hormone and Fertility Test and why its timing matters. The Cycling Hormones These are tested on day 3 as mentioned earlier because they are at their ‘baseline’ around the first few days of your cycle. FSH (follicle-stimulating hormone) FSH is made by the pituitary gland in the brain and is the primary driver of egg development. FSH stimulates the production of oestradiol and eggs (oocytes) during the first half of the menstrual cycle.  Your FSH on day 3 might tell us whether the body is working as we would expect, or a little bit harder to induce follicular growth which may indicate reduced ovarian reserve, suggesting the egg supply could be beginning to decline.  Oestradiol (E2) Oestradiol is the primary form of oestrogen produced by the ovaries, and it plays a complex, interconnected role with FSH. Oestradiol serves as the brakes for the brain’s production of FSH. It travels from the ovaries to the brain and signals it to dial down FSH levels.  This is why FSH and oestradiol are always measured together. Not only their results, but their interpretation relative to each other is important for our clinicians to determine whether there is anything going on.  LH (luteinising hormone) LH is best known as the hormone that surges dramatically at mid-cycle to trigger ovulation. But measuring it at baseline on day 3 also tells us something important. If LH is too high on day 3, it may signal a condition like polycystic ovary syndrome (PCOS). An elevated LH:FSH ratio in the early follicular phase is one of the hormonal patterns clinicians look for when investigating PCOS and irregular ovulation. AMH (anti-Müllerian hormone) AMH is one of the most valuable markers for assessing ovarian reserve, and it works quite differently from the cycling hormones.  Historically, it has been thought that AMH doesn’t fluctuate dramatically across the cycle in the same way, so could be measured at any point during the menstrual cycle. However, research does suggest there may be some variation, which is why at Hertility, we standardise AMH testing to the days 2-5 window. This allows us to negate any potential fluctuation and ensure our results are consistent and comparable over time. AMH tells us about egg quantity (how many follicles are available) but it’s important to note it doesn’t directly measure egg quality. It should always be interpreted alongside your other results and your clinical history. Thyroid hormones (TSH and free T4) Thyroid hormones don’t fluctuate with the menstrual cycle, so strictly speaking they don’t need to be tested on day 3. We include them in the same panel because thyroid dysfunction, both overactive and underactive thyroid can significantly disrupt ovulation, cycle regularity, and fertility outcomes. Testing them alongside your reproductive hormones gives a more complete picture of your overall hormonal health in a single sample. Androgens (including testosterone) Androgens like testosterone are relatively stable across the menstrual cycle, making cycle timing less critical for these markers. That said, testing during the early follicular phase, when oestrogen is at its lowest means androgens aren’t being masked or influenced by rising oestrogen levels. For women investigating conditions such as PCOS, elevated androgens are an important part of the diagnostic picture. Prolactin Prolactin can technically be tested on any day. What does affect prolactin is the time of day and lifestyle factors. Prolactin naturally rises during sleep and can remain elevated for some hours after waking. Stress, physical activity, and even eating can temporarily raise levels. This is why Hertility asks you to take your sample first thing in the morning, before eating or exercise, to capture the most stable reading. The science behind day 3 testing: what does the research actually say? Day […]

For years, women have been told to wait. Wait until the symptoms get worse.Wait for an appointment.Wait until it’s “clinically significant.” And so women wait, often with fatigue, irregular cycles, unexplained anxiety, weight changes, brain fog, pain, or the quiet, persistent feeling that something isn’t quite right. Not urgent enough for A&E. Not specific enough for a specialist referral. But not nothing either. This gap is where modern women’s healthcare loudly fails. And it’s exactly the space Hertility is trying to rebuild. So, we’re introducing Women’s Health GP Consultations to close that gap. Helping you bring your symptoms, test results and medical history into one joined-up consultation. It’s a space designed to give you clarity, not just reassurance, and a plan you can actually act on. We’re bringing you a consultation with a GMC Registered GP trained women’s hormonal and reproductive health. It’s medical care, informed by your test results, so you don’t have to start again. A Women’s Health GP will be there to: It’s general practice redesigned around women’s bodies and your lived experience. Because these days, getting an appointment isn’t always the same as getting help On paper, the NHS has never been busier. In August 2025 alone, there were over 27 million GP appointments in England, an increase of 11% per working day compared to pre-pandemic levels*. The demand is there. The doors are technically open. But access doesn’t always equal care. With short appointments and fragmented follow-ups make it hard to unpick complex hormonal symptoms. Many conditions don’t show up clearly in one blood test. Patterns take time and context matters.  This isn’t a failure of clinicians. It’s a failure of design, shaped by decades of neglect in women’s health. We can see women are falling through the cracks (it’s a tale as old as time) In a Hertility survey of nearly 1,000 users.  Crucially, these were not stories of advanced disease or specialist-level cases. They were stories of everyday medical uncertainty: These are conditions and symptoms woven into daily life, not medical outliers. They sit firmly within the scope of good general practice when time, expertise, and continuity are available. There’s a serious diagnosis to treatment gap Even when women do receive a diagnosis, care often stalls. Among Hertility users with known conditions such as PCOS, thyroid disorders, fibroids, or anaemia: This is not a failure of specialist medicine. It is the absence of ownership in the middle. Someone to say: this matters. This can be treated. Or this can safely be monitored. And while NHS diagnostic and treatment backlogs continue, with 24% of patients waiting over six weeks for diagnostic tests* and referral-to-treatment targets unmet since 2016, many women are left in limbo. Unsure whether to push, pause, or escalate. How Hertility is building women’s healthcare differently We founded Hertility because we’d seen first-hand how often women’s health concerns are dismissed, delayed, or oversimplified. Too often, symptoms are looked at in isolation. Too often, women are told everything is “normal” without anyone taking the time to explain what that actually means for them. By combining diagnostics, hormone-literate clinicians, and now, ongoing GP care, we’re creating a more reliable path from results to action. It’s the difference between being told “everything looks normal” and being helped to understand what normal means for you. What Women Actually Want From Care (It’s Simpler Than You Think) For many women, we hear the most powerful part of healthcare isn’t always the diagnosis or even the treatment. It’s being believed, understood, and guided toward the right next steps. We know that the future of women’s health won’t be built on apps alone, or tests alone, or even specialists alone. It will be built in the spaces between. Where insight becomes action. Where long-ignored conditions finally meet real medical solutions. Our new Women’s Health GP service isn’t about replacing what exists. It’s about rebuilding care in a way that finally works for women. In a world capable of extraordinary scientific progress, it shouldn’t be radical to expect clear pathways for conditions that affect 51% of the population.  We’re tired of waiting, so we’re building the future ourselves. From Deirdre O’Neill, Dr Helen O’Neill and Dr Natalie Getreu x Resources: https://researchbriefings.files.parliament.uk/documents/CBP-7281/CBP-7281.pdf

Experiencing persistent fatigue or low energy that just won’t shift, no matter how much you sleep or how many coffees you have? You’re not alone. Many women and people with cycles dismiss chronic tiredness as a normal part of a busy life, yet it can be a sign that something is going on. When fatigue becomes persistent, heavy, and impacts your daily life, it’s time to look beyond just needing more rest. Fatigue is a feeling of constant tiredness or weakness, and it can be physical, mental, or both. Low energy describes a lack of vigour or motivation. Whilst lifestyle factors – like a poor night’s sleep, stress, or a less-than-ideal diet – can certainly cause temporary dips, when these symptoms become chronic, it’s often a signal from your body that your delicate hormonal balance might be disrupted. This article will explore the common, and often overlooked, hormonal drivers behind feeling tired all the time and outline how taking our Advanced At-Home Hormone and Fertility Test can uncover the root causes of your symptoms. TAKE THE TEST → What Causes Fatigue and Low Energy? The causes of fatigue are diverse, ranging from simple lifestyle factors to underlying medical conditions. However, many of the most persistent and hard-to-diagnose cases in women often circle back to hormone health. Common Lifestyle and Medical Causes Before diving into the hormonal links, it’s important to rule out the most common causes of low energy: Sleep Deprivation: Lack of quantity or quality sleep. Sleep disorders like sleep apnoea are common culprits. Nutrient Deficiencies: Low levels of iron (leading to anaemia), Vitamin B12, and Vitamin D are strongly associated with fatigue. Stress and Mental Health: Chronic stress, anxiety, or depression can deplete both physical and mental reserves. Other Medical Conditions: Fatigue is a key symptom of conditions such as coeliac disease, chronic fatigue syndrome (ME/CFS), and heart disease. The Hormonal Connection: A Deeper Dive For many, general medical checks come back clear, yet the profound tiredness persists. This is where hormones often step in as the missing piece of the puzzle. Hormones act as chemical messengers throughout the body, regulating metabolism, sleep cycles, stress response, and reproductive health – all of which are intrinsically linked to your energy levels. How Hormones Affect Fatigue and Low Energy Several key hormones play critical roles in regulating your energy, and imbalances in any of them can lead to that heavy, constant feeling of being drained. 1. Cycling Hormones (Oestrogen, Progesterone, LH & FSH) The menstrual cycle is an intricately regulated process driven by the hypothalamic-pituitary-ovarian (HPO) axis. The fluctuation of key hormones – oestrogen (specifically estradiol), progesterone, luteinising hormone (LH) and follicle-stimulating hormone (FSH) – has a significant influence on central nervous system function, affecting energy metabolism, sleep architecture, and neuropsychiatric stability (Li et al., 2020). Oestrogen’s Role: Oestrogen generally acts as a boost; it can be linked to improved muscle function, mood, and sleep quality. When oestrogen peaks in the late follicular phase (leading up to ovulation), many women report feeling their most energetic. A notable dip in oestrogen – such as during the early follicular phase (the start of the cycle/period) or during perimenopause – is often associated with low mood and brain fog. Progesterone’s Role: Often called the calming hormone, progesterone rises sharply after ovulation (in the luteal phase). Progesterone has a sedative effect, primarily by enhancing the activity of GABA, the brain’s main inhibitory neurotransmitter. While this is great for promoting sleep, high progesterone during the pre-menstrual (PMS) week can be a key driver of that characteristic fatigue or sluggishness. Poor sleep quality due to a fall in progesterone just before a period can also lead to day-time exhaustion (Ennour-Idrisi et al., 2015). LH & FSH: These hormones, released by the pituitary gland, regulate the production of oestrogen and progesterone. While they don’t directly cause fatigue, measuring their levels is crucial for diagnosing reproductive health conditions (like PCOS) or age-related shifts (like perimenopause/menopause), which have fatigue as a key symptom. 2. Androgens (Testosterone, DHEAS & SHBG) Androgens are essential for vitality in women and people with menstrual cycles. Testosterone and its precursor, DHEAS, are powerful hormones linked to motivation, muscle mass, bone density, and energy metabolism. Testosterone’s Impact: A drop in testosterone can lead to decreased muscle mass, lower bone density, reduced libido, and a general sense of low energy (Bolour & Braunstein, 2005). Low testosterone levels often naturally occur with age or can be caused by certain hormonal contraceptives. Sex Hormone-Binding Globulin (SHBG): This protein acts as a transport mechanism, binding to sex hormones like testosterone and making them biologically inactive. If your SHBG levels are too high (often seen in high-oestrogen states or with certain medications), it can ‘hoover up’ your biologically active testosterone, leading to low energy and other symptoms, even if your total testosterone level is within the normal range (Szybiak-Skora et al., 2025). 💡 Find out what your hormones are telling you Take our Advanced At-Home Hormone and Fertility Test to uncover the root causes of your symptoms, including persistent fatigue and low energy. TAKE THE TEST → 3. Cortisol (The Stress Hormone) Cortisol is released by the adrenal glands and is part of the body’s natural “fight or flight” stress response. While essential in short bursts, chronic stress leads to chronically elevated cortisol, which eventually impacts energy regulation (Kumari et al., 2009). Chronic Stress and Adrenal Fatigue (Exhaustion): While “adrenal fatigue” isn’t a recognised medical diagnosis, prolonged high stress can lead to dysregulation of the HPA (Hypothalamic-Pituitary-Adrenal) axis, which manages cortisol. This dysregulation is linked to the symptoms of tired all the time and low energy women. Initial high cortisol can disrupt sleep, and later dysregulation can leave you feeling depleted and unable to manage stress. 4. Insulin Insulin regulates blood sugar, which is your body’s primary fuel source. When insulin is dysregulated (known as insulin resistance), your cells struggle to absorb glucose, leaving your body and brain starved of the energy they need. This common issue is a […]

Thyroid hormones are made in the thyroid gland and play a crucial role in regulating many different body functions. But what happens when these hormones get out of balance and what is a thyroid disorder? Read on to find out.  Quick facts: What are thyroid hormones? Thyroid hormones are incredibly important hormones for overall health. They play a crucial role in influencing many, many different bodily processes.   There are three thyroid hormones—TSH, T4 and T3. Each has a different function in the body which we’ll explain in a second.  TSH is made in the pituitary gland in the brain. TSH then stimulates the thyroid gland—a butterfly-shaped gland in your throat to produce T4 and T3. What are the different types of thyroid hormones? There are three main thyroid hormones: What do thyroid hormones do in the body? Thyroid hormones play an essential role in many different functions of the body, including: The thyroid hormone feedback loop Just like lots of hormones, our thyroid hormones are all linked—involved in what’s known as a feedback loop. Essentially they all depend on each other to work optimally.  Here’s how the thyroid feedback loop works: Can thyroid hormones become imbalanced? Yes. Thyroid imbalances, known as thyroid disorders, are really common and can disrupt many aspects of your health—bringing on a whole range of unwanted symptoms.  1 in 8 women are estimated to develop thyroid problems during their lifetime. Thyroid disorders are caused by either an underactive thyroid (known as hypothyroidism) or an overactive thyroid (hyperthyroidism). Let’s take a look at each in turn. Hypothyroidism: an underactive thyroid Hypothyroidism is when your thyroid isn’t producing enough T4 (and sometimes T3). This means you have an abnormally high level of TSH, compared to your T4 and/or T3 levels. Because of the thyroid hormone feedback loop, when T3 and T4 are low our brains will overcompensate. This means you’ll produce more TSH to try and boost your T3 and T4 levels. This results in the classic low T3 and T4 levels paired with high TSH reading seen in hypothyroidism. Symptoms of an underactive thyroid  Hypothyroid symptoms include: Having an underactive thyroid can also increase the risk of developing long-term health problems such as cardiovascular conditions, insulin resistance, nerve damage and a swollen enlarged thyroid (goitre).  Causes of an underactive thyroid Hypothyroidism can be caused by a range of factors including age, poorly balanced diets and pre-existing medical conditions like Polycystic Ovary Syndrome (PCOS). Additionally, taking certain medications such as oestrogen-containing hormonal contraception and high doses of steroids can interfere with thyroid function.  Treatments for an underactive thyroid Hypothyroidism is typically treated with a medication called Levothyroxine that replaces T4. Cytomel, a T3 replacement, may also be required in specific cases. Lifestyle changes can also improve your thyroid function. Eating iodine-rich foods like milk and dairy products and adding more white fish, eggs, beans, pulses or red meat into your diet can help. Stress is a big factor in many hormone imbalances and conditions. So, like always, try to find a stress management method that works for you. If you smoke, consider quitting. Cutting down on your alcohol intake can help too. Hyperthyroidism: An overactive thyroid An overactive thyroid means you’re making too much T4 and T3. This triggers your brain to make less TSH—giving the characteristic low TSH paired with high T3 and T4. Symptoms of hyperthyroidism: Causes of an overactive thyroid Much like an underactive thyroid, lifestyle factors like poor diet, smoking, alcohol and stress can cause an overactive thyroid.  Genetics, autoimmune disorders like diabetes or Grave’s disease in addition to long-term problems with cardiovascular health and weight loss are associated with an overactive thyroid. Excess iodine consumption has also been linked to an overactive thyroid. Be mindful of rich sources of iodine like kelp and seaweed and take extra care to check any supplements. Treatments for an overactive thyroid Prescription medications like carbimazole can be prescribed to decrease the function of your thyroid. Beta-blockers can also provide symptom relief from a racing heart or heart palpitations. If needed, surgical intervention to partially remove your thyroid gland can also be an option. Can a thyroid imbalance affect fertility? Thyroid disorders can affect your fertility indirectly, because of the various issues they can cause to your metabolism and other hormones. One study demonstrated that 76% of women who fixed their thyroid were able to conceive between 6 weeks to 1 year afterwards.  Thyroid disorders can indirectly cause: Why should I test my thyroid hormones? If you suspect you have an issue with your thyroid or are experiencing any hormonal symptoms, testing your thyroid levels is the best place to start to help you understand whether you may be suffering from a thyroid disorder.  Most thyroid function tests will not measure T3 unless you are known to have problems with your thyroid. This is because you are unlikely to have abnormal levels of T3 without having abnormal levels of TSH and/or T4. Resources:

Hormone replacement therapy (HRT) is a common treatment for easing menopause symptoms, like hot flashes, brain fog, joint pain, low mood and low libido. But how does it work and what are the signs you need hormone replacement therapy? Read on to find out. Quick facts: HRT explained Hormone Replacement Therapy for menopause is a treatment that uses hormones to relieve the symptoms of menopause and to prevent health problems that can occur after menopause.  The hormones commonly used in HRT are oestrogen, progesterone and sometimes testosterone. It does what it says on the tin—replaces the hormones that are declining in your body during this natural part of ageing, with synthetic or bioidentical hormones. These hormones mimic your natural hormones, relieving symptoms.  HRT can be taken in a variety of ways, including pills, patches, gels, sprays, vaginal cream and pessaries. The best method to take HRT will depend on your individual needs, preferences and medical history. Do you need HRT? You can take HRT to relieve menopause symptoms if you’re in perimenopause (the years leading up to menopause before your periods stop) or postmenopause.  Challenging symptoms like brain fog, night sweats, vaginal dryness, reduced sex drive, insomnia and concentration issues can interrupt your daily life. Hormone replacement therapy helps to restore hormonal balance to provide relief. Whether or not you’ll need HRT will depend on your symptoms and physiology and is always a personal choice. For personalised advice, you can book an appointment with one of our Menopause Specialists.  They can prescribe HRT based on your individual needs and preferences and can offer expert guidance on navigating symptoms and treatment options. Different types of HRT There are different types of HRT to choose from. Which type is right for you will depend on: HRT options can contain different hormones, including oestrogen, progestogen, a combination of both, and sometimes testosterone. HRT can be taken in different ways tablets, including patches, gels, sprays, implants, coils, or creams. It can also be taken using different regimens, including cyclical or sequential treatments, or continuous treatments.  Tablets Tablets are one of the most common ways of taking HRT. You usually take them once a day. Tablets are available in both oestrogen-only and as combined HRT.  Although it’s small, the risk of developing blood clots is higher with tablets compared to other HRT methods like patches, gels and sprays. Skin patches HRT patches are available in both oestrogen-only and combined. They are stuck to the skin, usually on the lower half of your body, and gradually release small amounts of hormones through the skin. You’ll usually change your skin patch every few days. Patches could be a preferred option if you have difficulty swallowing tablets, get indigestion or are likely to forget to take tablets. Some patches can leave marks and cause redness or irritation. Oestrogen skin gels and sprays You apply oestrogen-only skin gels by smoothing them onto your skin. Apply sprays by spraying them on the inside of your arm or thigh once a day. Your body absorbs the oestrogen gradually. Vaginal oestrogen Low-dose vaginal oestrogen is also available in tablets, pessaries, creams or vaginal rings that you insert into your vagina. This can help to provide relief for particular menopause symptoms like vaginal dryness and pain during sex (dyspareunia). Testosterone Like oestrogen and progesterone, menopause also causes your testosterone to decline. This can make you feel tired, unmotivated and low in libido. While testosterone isn’t currently licensed to treat menopause symptoms in the UK, specialists may prescribe it. It’s given in the form of a gel that you can rub over the skin where it’s gradually absorbed. Although uncommon, possible side effects of taking testosterone include acne, unwanted hair growth and weight gain. Intrauterine system (IUS) or Mirena coil If you have a womb and are using oestrogen-only HRT, you’ll need to also take a form of progesterone HRT to protect against endometrial cancer. You can do this with the Mirena coil, an intrauterine system (IUS). Inserted into your womb, the Mirena coil gradually releases progestogen (levonorgestrel) into your body. Once inserted, the Mirena coil can stay in place for up to five years and double up as contraception to prevent pregnancy. Benefits and risks of HRT Like other medications, there are benefits and risks associated with HRT. Benefits of HRT Most of the symptoms of menopause are associated with declining oestrogen levels. People have found that HRT is useful to manage symptoms including:  There are several long-term effects associated with low oestrogen. Taking HRT can help to reduce the risk of: Risks of HRT The risks of any serious side effects are usually very low, and depend on: HRT can slightly increase the risk of breast cancer. If you’ve had breast cancer or have a family history of it you’ll usually be advised not to take HRT.  Currently, the risk of breast cancer when using HRT has been found to be an extra 5 in every 1000 women who take combined HRT for 5 years. The risk increases the longer you take it, and the older you are. It falls again after you stop taking it.  Oral HRT can increase the risk of blood clots and in rare cases, stroke. If your medical history would indicate that you are at an increased risk of blood clots or strokes you should be recommended HRT patches, spray or gel rather than tablets, which have been found to not carry this risk. Weighing up the risks and benefits of taking HRT needs to be considered on an individual basis. It has been found in more recent studies that usually the benefits outweigh the risks and why HRT is now so commonly used. If you haven’t had a hysterectomy, you’ll need to take oestrogen and progesterone combined to protect against cancer. Oestrogen thickens the womb lining which can increase the risk of developing endometrial cancer. Progesterone helps to protect against it by ensuring the lining is shed regularly. The HRT timeline: How long before results? Once […]