# 14 | How to Check Your Fertility

Whether you are thinking about having children soon, at some point in the future, or simply want a clearer picture of your reproductive health, understanding your fertility is one of the most valuable things you can do for your body. For many women, fertility remains something of a mystery, like a topic only raised when conception becomes a goal or when it starts to feel difficult. At HER, we believe that knowledge is something you deserve at every stage, not only when you are actively trying.

So here is what you actually need to know.

Why Fertility Changes Over Time

Female fertility is not a fixed state as it shifts across your reproductive years, shaped by age, hormones, and overall health. You are born with all the eggs you will ever have and that reserve gradually declines as you get older. This decline is relatively gradual through your twenties and early thirties, but tends to accelerate after the age of 35, which is why age is consistently identified in the research as the most significant single factor in fertility.

Alongside egg quantity, egg quality also matters and this too is influenced by age, as well as by lifestyle factors including sleep, nutrition, stress, and certain underlying health conditions. Conditions like polycystic ovary syndrome (PCOS), endometriosis, thyroid disorders and premature ovarian insufficiency can all affect fertility, sometimes without obvious symptoms. This is part of why proactive testing rather than waiting for a problem to emerge is becoming an increasingly important part of reproductive healthcare.

When It Makes Sense to Check

There is no single right time to look into your fertility and you do not need to be trying to conceive to do so. Many women choose to check their hormones and ovarian reserve in their late twenties or early thirties simply to understand where they stand particularly if they are considering delaying a family or if they have a condition they know can affect reproductive health.

If you have been trying to conceive for six months or more and are over 35, most clinical guidelines recommend seeking a fertility evaluation at that point. For those under 35 without known risk factors, the typical guidance is to seek assessment after twelve months of trying without success though this is a general threshold, not a reason to wait if something feels off.

What Fertility Testing Actually Involves

Fertility testing for women generally falls into two categories: hormone blood tests and structural assessments of the reproductive system.

Hormone testing looks at the levels of key reproductive hormones, including follicle-stimulating hormone (FSH), luteinising hormone (LH), oestradiol, and anti-Müllerian hormone (AMH). Of these, AMH is particularly useful as a marker of ovarian reserve. It gives an indication of how many eggs remain, which helps to contextualise your fertility picture relative to your age. It is worth noting that AMH reflects quantity, not quality, so it forms one part of a broader assessment rather than the whole story.

Onto structural assessments, which are typically carried out in a clinical setting,  can include transvaginal ultrasound to count antral follicles (a further measure of ovarian reserve) and to examine the uterus and ovaries, as well as more specialist investigations such as hysterosalpingography (HSG) to check whether the fallopian tubes are open and unobstructed. These tests are usually recommended when there is a clinical reason to investigate further, rather than as a first step.

What Can Affect Your Results

Hormone levels fluctuate throughout the menstrual cycle, which means timing your test correctly is important for accurate results. FSH and LH are typically measured in the early follicular phase (days two to five of your cycle), while progesterone is usually tested around seven days after ovulation to assess whether ovulation has occurred. AMH is more stable and can generally be tested at any point in the cycle.

Lifestyle factors including significant stress, rapid weight changes, and certain medications can all influence hormone levels, so it is worth being open with your clinician about these when interpreting results.

What Comes Next

Receiving your results is the beginning of a conversation, not a verdict. Hormonal imbalances identified through testing are often addressable through lifestyle changes, medication, or specialist treatment and even a lower ovarian reserve does not close the door on pregnancy. What it does is give you and your care team the information needed to make genuinely informed decisions, whether that means beginning to try sooner, exploring egg freezing, or simply continuing to monitor your health over time.

If you are navigating fertility questions and are not sure where to start, speaking with your GP or a gynaecologist is always a reasonable first step. You deserve answers that are specific to your body not a generic waiting game.

Medical Disclaimer: This article is intended for informational and educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional regarding fertility concerns or treatment decisions. HER is not a medical provider.