The NHS won't investigate fertility until you've been trying for 12 months (6 months if you're 36 or older). That waiting period can feel like an eternity when every month matters. A private fertility blood test checks AMH, FSH, thyroid, progesterone, and the nutritional foundations of conception right now. A comprehensive panel like the TrueVitals Ultimate covers all of these alongside 114 total biomarkers for £349 — the data you need to start informed, not anxious.
NICE CG156 recommends that couples should be referred for investigation after 12 months of trying to conceive, or 6 months if the woman is 36 or older. After referral, NHS waiting times for initial fertility assessment average 6 weeks to 4 months depending on your area. The initial NHS investigation typically includes FSH, LH, progesterone, and sometimes thyroid (TSH only). AMH is not routinely available on the NHS in many areas without a specialist referral.
For a woman aged 34, that pathway looks like this: try for 12 months, wait 2 to 3 months for an appointment, get basic blood tests, wait for results, get referred to a fertility specialist, wait another 2 to 4 months. She is now 35 or 36, and the investigation has only just begun. Ovarian reserve declines with every passing month. Time is the one resource you cannot get back.
A private fertility blood test takes 48 hours and tests everything the NHS would test plus the markers it wouldn't. If the results reveal a treatable issue (subclinical hypothyroidism, vitamin D deficiency, low progesterone, elevated prolactin), intervention can begin immediately. If the results are normal, you have reassurance and a baseline for future comparison. Either outcome is better than waiting 12 months for permission to investigate.
Not just reproductive hormones. The full systems that affect conception, implantation, and early pregnancy.
AMH measures the quantity of remaining eggs. It can be tested on any day of the cycle, unlike FSH and oestradiol. A higher AMH suggests a larger egg pool. Important: AMH measures quantity, not quality. It does not predict your chance of conceiving naturally in any given month. It is most useful for timing decisions (how urgent is treatment?), predicting IVF response, and egg freezing decisions. A low AMH does not mean you cannot conceive. A high AMH does not guarantee you will.
FSH stimulates egg development. High FSH can indicate reduced ovarian reserve (the ovaries need more stimulation). LH triggers ovulation; an elevated LH:FSH ratio can indicate PCOS. Oestradiol supports follicle development. These markers must be tested on days 2 to 5 of your menstrual cycle for accurate interpretation.
A progesterone test on day 21 of a 28-day cycle (7 days before expected period) confirms whether ovulation occurred. Progesterone above 30 nmol/L strongly suggests ovulation. Below 16 nmol/L suggests anovulation. If your cycles are irregular, your "day 21" shifts accordingly — test 7 days before your expected period, not literally on day 21.
Thyroid function is critical for conception and early pregnancy. Endocrinologists recommend a TSH below 2.5 mIU/L when trying to conceive. The NHS reference range extends to 4.0 to 4.5 mIU/L, meaning a woman with TSH of 3.5 is "normal" by NHS standards but above the optimal fertility threshold. Subclinical hypothyroidism is associated with increased miscarriage risk and impaired ovulation. Thyroid antibodies (Anti-TPO) can be elevated even when TSH is normal, indicating Hashimoto's thyroiditis that may worsen during pregnancy. Thyroid blood test guide.
Elevated prolactin outside of pregnancy and breastfeeding can suppress ovulation and disrupt menstrual cycles. Causes include stress, certain medications, hypothyroidism, and prolactinoma (a benign pituitary tumour). It is treatable, often dramatically so, but must be tested to be found. The NHS does not routinely test prolactin in early fertility investigations.
Vitamin D deficiency is associated with reduced fertility and poorer IVF outcomes. Folate is critical for neural tube development in the first weeks of pregnancy (before most women know they're pregnant). Ferritin below 30 ng/mL impairs energy and increases the risk of pregnancy-related anaemia. B12 deficiency is associated with recurrent early pregnancy loss. These are correctable, but only if tested. Vitamin deficiency guide.
Insulin resistance underlies the majority of PCOS cases and directly disrupts ovulation. Fasting insulin and HOMA-IR detect it years before HbA1c rises. Undiagnosed coeliac disease is associated with unexplained infertility and recurrent miscarriage. Testosterone and SHBG identify androgen excess patterns consistent with PCOS. PCOS blood test guide. Insulin resistance guide.
The TrueVitals Ultimate panel covers AMH, full reproductive hormones, complete thyroid with antibodies, metabolic depth, and nutritional foundations. 114 biomarkers. Results in 48 hours. £349. One blood draw covers both the fertility-specific and whole-health picture.
Some fertility markers are cycle-dependent. Others can be tested any day. Here is when to book each component.
FSH, LH, oestradiol. These must be tested in the early follicular phase for accurate interpretation. Day 1 is the first day of your period. Book your blood test for day 2, 3, 4, or 5.
Progesterone (ovulation confirmation). Test 7 days before your expected period. For a 28-day cycle, that's day 21. For a 32-day cycle, test on day 25. For irregular cycles, discuss timing with your provider.
AMH, thyroid (TSH, Free T4, Free T3, antibodies), prolactin, vitamin D, B12, folate, ferritin, HbA1c, fasting insulin, lipids, liver, kidney, FBC. These are not significantly affected by cycle day.
Practical approach: book one comprehensive test on days 2 to 5 of your cycle (covers FSH, LH, oestradiol plus all cycle-independent markers). Then book a progesterone-only test on day 21. This two-test approach gives you the complete fertility picture. The TrueVitals panel covers everything in the first draw. A standalone progesterone test for day 21 can be arranged separately.
If everything looks normal: that is genuinely reassuring. It means your hormonal, thyroid, and nutritional foundations are in place. Continue trying with confidence. Retest in 6 months if you haven't conceived. The comparison between tests may reveal subtle shifts.
If a treatable issue is found: subclinical hypothyroidism (TSH above 2.5), low vitamin D, low ferritin, elevated prolactin, or insulin resistance are all correctable. Many women conceive after addressing these foundations. Take your results to your GP. The data makes the conversation specific and actionable.
If AMH is low: this indicates reduced ovarian reserve but does not mean you cannot conceive. It does mean time may be a factor. Discuss with a fertility specialist sooner rather than later. Your results provide the data they need for an informed consultation. Consider whether egg freezing or accelerated investigation is appropriate.
If you're considering IVF: a comprehensive panel provides the baseline your fertility clinic needs. Many IVF clinics charge £200 to £500 for their own pre-treatment blood work, often testing fewer markers than a comprehensive private panel. Arriving with a recent comprehensive panel can reduce duplication and give your consultant a broader picture.
Most fertility blood tests give you AMH, FSH, and a few hormones in isolation. The TrueVitals report analyses fertility markers alongside thyroid, metabolic, and nutritional data. If your AMH is normal but your TSH is 3.8, that thyroid finding may be the reason you're not conceiving, and a standalone fertility test would have missed it. If your progesterone confirms ovulation but your fasting insulin is elevated and your ferritin is 18, those metabolic and nutritional findings are undermining an otherwise functional cycle. The cross-system analysis identifies these connections. A medical professional reviews every report.
114 biomarkers including AMH, full reproductive hormones, thyroid with antibodies, metabolic health, and nutritional foundations. The complete fertility picture. Results in 48 hours. £349.
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