Women's Health Blood Test UK: What to Test, When to Test & What Your Results Mean

1. Why women need different blood tests

Most routine blood panels were designed around male physiology. Reference ranges for ferritin, testosterone, and haemoglobin were historically established using predominantly male study populations. The result: “normal” ranges that may not reflect optimal health for women.

Women also face conditions that either don't exist in men or are dramatically more common in women:

• Iron deficiency — affects roughly 1 in 4 UK women of reproductive age, primarily due to menstrual blood loss
• Thyroid disorders — women are 5-10 times more likely to develop thyroid problems than men
• Vitamin D deficiency — particularly prevalent in the UK where 1 in 6 adults are deficient, with higher rates in women over 65
• PCOS — affects 1 in 10 UK women and is often diagnosed late (or not at all)
• Osteoporosis — women lose up to 20% of their bone density in the 5-7 years after menopause

A standard NHS blood panel won't catch most of these unless you already have symptoms. The right blood test at the right time can flag problems years before they become clinical.

2. Iron and ferritin: the most common deficiency in women

Iron deficiency is the world's most common nutritional deficiency, and women bear the brunt of it. The WHO estimates that 30% of non-pregnant women globally are anaemic, with iron deficiency as the leading cause.

The NHS considers ferritin below 15 µg/L as deficient. But research published in the BMJ suggests that symptoms of iron deficiency — fatigue, brain fog, hair loss, breathlessness — can appear at ferritin levels below 30 µg/L, and many functional medicine practitioners consider 50–100 µg/L optimal for women.

Key iron markers to test:

• Ferritin — your iron storage protein. The single most useful marker for detecting early iron depletion
• Serum iron — circulating iron in your blood (fluctuates daily, less reliable alone)
• Transferrin saturation — the percentage of iron-binding capacity being used; below 20% suggests deficiency
• Full blood count (FBC) — haemoglobin, MCV (mean cell volume), and MCH reveal whether iron depletion has progressed to anaemia

Who should test regularly: any woman with periods (especially heavy periods), vegetarians and vegans, pregnant women or those planning pregnancy, endurance athletes, and anyone experiencing unexplained fatigue or hair loss.

3. Thyroid: why women are 5–10x more likely to have problems

The thyroid controls metabolism, energy, mood, weight, menstrual regularity, and fertility. Thyroid disorders are overwhelmingly more common in women — the British Thyroid Foundation estimates that thyroid conditions affect 1 in 20 people in the UK, with women 5–10 times more likely to be affected.

The problem is that the NHS typically only tests TSH (thyroid stimulating hormone). If TSH is within range — even at the edges — many GPs will declare your thyroid “fine.” But TSH alone can miss subclinical thyroid disease, which NICE NG145 acknowledges affects up to 8% of women.

A comprehensive thyroid panel should include:

• TSH — the pituitary's thermostat signal
• Free T4 — the main hormone produced by the thyroid
• Free T3 — the biologically active hormone that drives metabolism
• TPO antibodies — detects Hashimoto's thyroiditis, the most common cause of hypothyroidism in the UK

Thyroid symptoms — fatigue, weight gain, dry skin, feeling cold, brain fog, irregular periods — overlap with iron deficiency, perimenopause, and depression. This is why testing matters: you can't fix what you haven't measured. Read our full thyroid blood test UK guide for detailed ranges and interpretation.

4. Female hormones: oestradiol, progesterone, FSH, LH, and more

Your reproductive hormones don't just control fertility — they influence bone density, cardiovascular health, mood, sleep, skin, and cognitive function. Understanding your hormone levels gives you a window into your overall health, not just your reproductive status.

The key markers:

• Oestradiol (E2) — the primary oestrogen. Regulates menstrual cycle, bone density, cardiovascular protection, and mood. Declines progressively from late 30s
• Progesterone — produced after ovulation. Supports the luteal phase, pregnancy, sleep, and anxiety regulation. Day 21 testing confirms ovulation
• FSH (follicle stimulating hormone) — rises as ovarian reserve declines. The primary marker GPs use to assess perimenopause and menopause
• LH (luteinising hormone) — triggers ovulation. The LH:FSH ratio is important for PCOS diagnosis
• Testosterone — women produce testosterone too. Low levels cause low libido, fatigue, and reduced muscle mass; high levels may indicate PCOS
• SHBG (sex hormone binding globulin) — binds testosterone and oestradiol. Low SHBG means more free (active) hormones; high SHBG can mask adequate production
• Prolactin — elevated levels can cause irregular periods and are associated with pituitary conditions
• DHEA-S — an adrenal hormone that declines with age. Linked to energy, mood, and immune function

The Helvy Hormone Female panel (£119) tests all of these markers from a single home blood draw.

5. Vitamin D and bone health

The UK sits between latitudes 50–60°N, which means from October to March the sun isn't strong enough to trigger vitamin D synthesis in the skin. The National Diet and Nutrition Survey found that approximately 1 in 6 UK adults have deficient vitamin D levels (<25 nmol/L), with rates significantly higher in women over 65.

Vitamin D matters for women beyond bone health. Research published in the Lancet Diabetes & Endocrinology links vitamin D status to immune function, mood regulation, and pregnancy outcomes. Deficiency during pregnancy is associated with increased risk of pre-eclampsia and gestational diabetes.

What to test and what the numbers mean:

The NHS recommends that everyone in the UK takes a 10 µg (400 IU) supplement during autumn and winter. If your blood test shows deficiency, your GP may prescribe a higher loading dose. For more detail, see our vitamin D deficiency UK guide.

6. When in your cycle to get tested

Hormone levels change dramatically across your menstrual cycle. Testing at the wrong time can give misleading results. Here's the timing that gives the most clinically useful baseline:

If you're on hormonal contraception (combined pill, patch, ring), your natural hormone levels are suppressed. FSH, LH, oestradiol, and progesterone results won't reflect your baseline — you'd need to stop contraception for at least one full cycle to get a meaningful reading. Discuss this with your GP first.

7. What to test at every age: 20s, 30s, 40s, 50s+

20s — build your baseline

Most women in their 20s have never had a comprehensive blood test. This is the decade to establish your personal baseline — values you can compare against for the next 30 years.

• Full blood count, iron, ferritin
• Thyroid (TSH + Free T4)
• Vitamin D, B12, folate
• Liver and kidney function
• HbA1c (blood sugar baseline)
• If symptoms: full hormone panel

30s — fertility awareness + metabolic shifts

Ovarian reserve begins declining from the mid-30s. If you're planning pregnancy in the next few years, testing AMH (anti-Müllerian hormone) gives an indication of remaining egg supply. Your metabolic rate also begins to slow, making HbA1c and lipid panels more relevant.

• Everything from the 20s panel
• AMH (if planning pregnancy)
• Full lipid panel (total cholesterol, HDL, LDL, triglycerides)
• Insulin (fasting) if PCOS suspected
• Full hormone panel if symptoms emerging

40s — perimenopause watch

Perimenopause typically begins in the mid-40s (sometimes earlier). Symptoms can start before blood tests show obvious changes. Establishing a hormone baseline now lets you track the transition objectively rather than guessing.

• FSH, oestradiol, progesterone
• Full thyroid panel (TSH, FT4, FT3, TPO antibodies)
• Vitamin D + calcium (bone health monitoring begins)
• Cardiovascular markers (ApoB, Lp(a), hs-CRP) — cardiovascular risk rises sharply post-menopause
• HbA1c, fasting insulin

50s+ — post-menopause and prevention

After menopause, oestrogen's protective effect on the cardiovascular system and bones is gone. The British Heart Foundation notes that women's cardiovascular risk catches up with men's within a decade of menopause.

• Full cardiovascular panel (ApoB, Lp(a), hs-CRP, lipids, HbA1c)
• Vitamin D + calcium + phosphate
• Full thyroid panel
• Iron and B12 (absorption decreases with age)
• Kidney and liver function
• If on HRT: oestradiol levels to check therapeutic range

8. Perimenopause and menopause: the hormonal cliff edge

Perimenopause is the transition period leading to menopause (defined as 12 consecutive months without a period). It typically lasts 4–8 years and can start from age 40 — sometimes earlier. During this time, oestradiol fluctuates wildly before declining, progesterone drops as ovulation becomes irregular, and FSH gradually rises.

NICE NG23 states that in women over 45 with typical symptoms, menopause can be diagnosed clinically without blood tests. However, blood tests are essential for:

• Women under 45 with suspected early menopause
• Ruling out thyroid disease (symptoms overlap significantly)
• Women on HRT who need dose monitoring
• Distinguishing perimenopause from other hormonal conditions

Key perimenopause markers:

• FSH >25 IU/L — on two tests 4–6 weeks apart, strongly suggests perimenopause
• Oestradiol declining or erratic — may swing between very high and very low in the same cycle
• Progesterone low — indicates anovulatory cycles (no ovulation)
• TSH — rule out thyroid dysfunction, which causes identical symptoms

If you're experiencing hot flushes, night sweats, irregular periods, mood changes, brain fog, joint pain, or sleep disruption in your 40s, blood tests can confirm whether hormones are the cause — or whether something else needs investigating. Our GLP-1 and perimenopause guide covers additional considerations for women taking weight-loss medications during this transition. For a deeper dive into menopause blood testing specifically, see our complete menopause blood test guide.

9. Fertility markers: what to check before trying to conceive

If you're planning pregnancy, a pre-conception blood test can catch issues that are far easier to fix before conception than during pregnancy. The NHS advises taking folic acid from at least one month before conception, but rarely recommends comprehensive blood work.

Pre-conception blood panel:

• Ferritin — iron demands double during pregnancy; starting with low stores increases anaemia risk
• Folate — critical for neural tube development. Blood test confirms supplementation is working
• Vitamin D — deficiency linked to pre-eclampsia, gestational diabetes, and preterm birth
• Vitamin B12 — essential for fetal neurological development
• TSH — subclinical hypothyroidism can cause miscarriage and developmental issues; ideally TSH should be below 2.5 mIU/L pre-conception
• Rubella immunity — GP can check; non-immune women need vaccination before pregnancy
• HbA1c — screens for undiagnosed diabetes or pre-diabetes, both of which increase pregnancy complications

If you've been trying for over a year (or 6 months if you're over 35), the NICE CG156 fertility guidelines recommend hormone testing (FSH, LH, oestradiol, progesterone), AMH for ovarian reserve, and testosterone/SHBG to rule out PCOS.

10. PCOS: the blood test pattern your GP might miss

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age, affecting 1 in 10 UK women. It takes an average of over 2 years and 3 doctors to get a diagnosis, partly because the blood test pattern isn't always obvious if you're only testing one or two markers.

The classic PCOS blood test pattern:

• Raised testosterone (total or free) — the most consistent hormonal finding in PCOS
• Low or low-normal SHBG — means more free testosterone is bioavailable, driving symptoms like acne and hirsutism
• Raised LH with normal FSH — the classic elevated LH:FSH ratio (though not present in all women with PCOS)
• Raised fasting insulin — insulin resistance is present in 50–80% of women with PCOS, regardless of weight
• Raised DHEA-S — adrenal androgen excess, particularly in lean PCOS
• Normal or slightly raised HbA1c — downstream effect of insulin resistance

The Rotterdam criteria (endorsed by NICE) require 2 of 3: irregular cycles, clinical/biochemical hyperandrogenism (raised testosterone), and polycystic ovaries on ultrasound. Many GPs test only testosterone — missing the insulin resistance, SHBG, and adrenal components that complete the picture.

If you suspect PCOS, a comprehensive panel including testosterone, SHBG, DHEA-S, fasting insulin, LH, FSH, and HbA1c gives far more clinical insight than a single testosterone reading.

11. What the NHS tests vs what women actually need

The NHS is a symptom-driven system. If you present with fatigue, your GP will likely request FBC, ferritin, TSH, and possibly B12. What they're unlikely to test proactively:

This isn't a criticism of the NHS — it's a resource-constrained system designed to treat illness, not optimise wellness. Private testing fills the gap between “something is already wrong” and “let's catch it early.” For a full breakdown, see our NHS vs private blood test comparison.

12. Reference ranges vs optimal ranges for women

NHS reference ranges define the middle 95% of the tested population. If you fall within range, you're “normal.” But “normal” doesn't mean optimal. A ferritin of 16 µg/L is technically within range but would leave most women feeling exhausted.

These optimal ranges are informed by research from the BMJ, The Lancet, and NICE guidelines. They represent the levels at which symptoms are least likely and long-term health outcomes are best — not just the absence of disease. For a full breakdown, see our blood test results explained guide.

13. Your action plan

Don't wait for symptoms to become severe enough for your GP to investigate. Here's a practical framework:

1. Get a baseline in your 20s or early 30s. Even if you feel perfectly fine, a comprehensive panel gives you a personal reference point. What's “normal for you” matters more than population averages.
2. Retest annually or when symptoms appear. The NHS Health Check every 5 years isn't frequent enough to catch early changes. Annual testing lets you spot trends before they become problems.
3. Time your test correctly. Day 2–5 for hormones, fasting for lipids and iron, before 10am for cortisol and TSH. Getting this right makes your results far more useful.
4. Share results with your GP. Private blood tests complement NHS care — they don't replace it. If anything is out of range, your GP needs to know. UKAS-accredited lab results carry clinical weight.
5. Track changes over time. A single blood test is a snapshot. Trends across multiple tests are where the real insight lies — a slowly declining ferritin, a gradually rising TSH, or a worsening lipid profile tells a story that one test never can.

14. Frequently asked questions

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