Pre-conception and fertility blood test,
Harley Street, London.
A bespoke panel covering the nutritional, hormonal, thyroid and immunity markers UK pre-conception guidance recommends checking before trying to conceive. Reviewed by a GMC-registered doctor before booking. Anchored to NHS pre-conception advice and the UK Green Book immunity chapters. One blood draw at 134 Harley Street.
Quick answer
A pre-conception blood test typically covers folate, vitamin B12, vitamin D, ferritin (iron stores), TSH and free T4 (thyroid function), HbA1c (diabetes risk in pregnancy), and immunity status for rubella, varicella (chickenpox) and hepatitis B per the UK Green Book. AMH and FSH may be added when characterising ovarian reserve in women trying to conceive. NHS pre-conception guidance recommends 400 micrograms folic acid daily before conception and through the first 12 weeks of pregnancy.
Onsite laboratory: samples are processed in the same building within minutes of collection, never in external transit. Faster turnaround, no sample degradation, results you can trust.
What is included
- Folate, vitamin B12, vitamin D: NHS recommends folic acid 400 micrograms daily before conception and through the first 12 weeks. We confirm baseline status and identify any deficiency to address.
- Ferritin and iron studies: heavy or irregular bleeding before conception can deplete iron stores. Pregnancy demand increases iron requirements significantly.
- TSH and free T4: uncorrected hypothyroidism increases miscarriage and preterm risk. Subclinical hypothyroidism is more common than recognised.
- HbA1c: pregnancy increases the risk of gestational diabetes; a pre-conception baseline is useful, particularly for women with a family history of type 2 diabetes.
- Rubella, varicella and hepatitis B immunity: per UK Green Book Chapters 28, 34 and 18. Non-immune women planning pregnancy should be offered MMR (rubella) or varicella vaccination at least 1 month before trying to conceive (these are live vaccines).
- AMH and FSH (where indicated): in women trying to conceive who want to characterise ovarian reserve. Most useful in women over 35 or with cycle irregularity.
Why pre-conception bloods matter
The 3 to 6 months before conception is the most cost-effective time to address modifiable factors. Folate replete reduces the risk of neural tube defects. Iron replete reduces fatigue and improves pregnancy reserve. Thyroid optimisation reduces miscarriage risk. Immunity check identifies women who would benefit from MMR or varicella vaccination before pregnancy (these are live vaccines that should not be given during pregnancy).
The panel is also reassuring: most women come back fully replete and immune, which is a useful starting baseline for what follows.
When in your cycle these tests should be taken
Fertility bloods are the most timing-sensitive tests we run. Some have to fall in a specific window to mean anything, one can be taken on any day, and getting this wrong is the commonest reason a fertility panel has to be repeated.
AMH: any day of the cycle
Anti-Mullerian hormone is produced by developing follicles and stays relatively steady across the cycle, so unlike the others it does not need to be timed. If your appointment is easier in the middle of the month, AMH is unaffected.
FSH, LH and oestradiol: days 2 to 5
These are read against the early follicular phase, counting the first day of full bleeding as day 1. Outside that window the reference ranges do not apply, and an FSH taken mid-cycle can look reassuring or alarming for reasons that have nothing to do with ovarian reserve.
Progesterone: 7 days before your next period, not day 21
Progesterone confirms whether ovulation happened, and it peaks in the mid-luteal phase, roughly a week before the next period is due. "Day 21" is shorthand that only works for a 28-day cycle. If your cycle runs to 35 days, the equivalent point is around day 28, and testing on day 21 is a common way to be told incorrectly that you did not ovulate.
Hormonal contraception changes what these tests show
Combined hormonal contraception suppresses FSH, LH and oestradiol, and modestly lowers AMH. Ovarian reserve testing taken while on the pill can therefore read lower than your true baseline. This does not always mean waiting, but it does mean the result has to be interpreted knowing you are on it, so tell us at the design stage rather than after.
Stop high-dose biotin first
Biotin interferes with many laboratory immunoassays, including thyroid function and several hormone assays, and both the MHRA and FDA have warned about it. It is the main ingredient in most hair, skin and nail supplements, and in a good number of pre-conception multivitamins. Stop it 48 to 72 hours before your appointment and tell us you have been taking it.
What AMH can tell you, and what it cannot
AMH is a good measure of ovarian reserve, meaning roughly how many follicles remain, and it is genuinely useful for predicting how the ovaries will respond to stimulation in IVF. That is what it was validated for and it does that job well.
It is not a measure of whether you can conceive naturally, and it does not tell you how long you have. A low AMH in a woman with regular cycles and no fertility problems does not reliably predict difficulty conceiving or a shorter window to try, and a reassuring AMH does not rule out other causes of subfertility. It says nothing about egg quality, tubal patency or your partner's contribution, and the marketing around at-home "fertility scores" persistently blurs that line.
We will still run it where it is useful, and we will tell you which of those two things your result is actually answering. If the question you are really asking is "am I likely to struggle", that is a conversation for a fertility specialist with a scan and a full history, not a single number from a blood test.
FAQs
What day of your cycle should you test AMH?
Any day. Anti-Mullerian hormone is produced by developing follicles and stays relatively steady across the cycle, so unlike FSH it does not need to be timed. That makes it the one fertility marker you can book around your diary rather than around your cycle.
When should progesterone be tested to confirm ovulation?
Roughly 7 days before your next period is due, which is the mid-luteal peak. "Day 21" is shorthand that only holds for a 28-day cycle. In a 35-day cycle the equivalent point is around day 28, and testing on day 21 instead is one of the commonest reasons a woman is told incorrectly that she did not ovulate.
Does AMH tell you if you can get pregnant?
No. AMH measures ovarian reserve, meaning roughly how many follicles remain, and it is genuinely good at predicting how the ovaries will respond to stimulation in IVF. It does not reliably predict natural conception or how long you have to try. A low AMH in a woman with regular cycles and no fertility problems does not mean you will struggle, and a reassuring AMH does not rule out other causes of subfertility. It says nothing about egg quality, tubal patency or your partner. If the question is whether you are likely to struggle, that needs a fertility specialist with a scan and a full history, not a single blood marker.
Can you test ovarian reserve while on the pill?
You can, but the result needs interpreting with that in mind. Combined hormonal contraception suppresses FSH, LH and oestradiol and modestly lowers AMH, so ovarian reserve testing on the pill can read lower than your true baseline. It does not always mean waiting, but tell us at the panel design stage rather than afterwards so the interpretation accounts for it.
When should I get pre-conception bloods?
NHS pre-conception guidance recommends starting 400 micrograms folic acid daily before conception and through the first 12 weeks of pregnancy, and checking rubella, varicella and hepatitis B immunity status. A pre-conception bloods workup is most useful in the 3 to 6 months before trying to conceive, so any identified deficiency or non-immunity has time to be addressed (immunisation if needed, folate replete, thyroid optimised, iron replete).
What does the panel typically include?
A typical pre-conception panel covers folate, vitamin B12, vitamin D, ferritin (iron stores), TSH and free T4 (thyroid function, particularly relevant in pregnancy), HbA1c (pregnancy increases diabetes risk), and immunity markers for rubella, varicella (chickenpox) and hepatitis B per the UK Green Book chapters. In women under 35 trying to conceive, AMH (anti-Müllerian hormone, where available) and FSH on cycle day 2-5 are sometimes added to characterise ovarian reserve.
How much does it cost?
Every pre-conception panel is custom-built around your specific question, with AMH, fertility-axis and immunity markers added based on context. We confirm the exact price in writing before booking.
What if I am already pregnant?
NHS antenatal care covers the routine pregnancy bloods. Private testing in early pregnancy is most useful for non-routine markers (TSH for women with a history of thyroid disease, ferritin for women with a history of heavy menstrual bleeding before conception) and for women who want additional reassurance alongside their NHS care. We work alongside your NHS antenatal team, not in place of it.
What about my partner?
For couples investigating subfertility, we can design a male partner panel covering total testosterone, SHBG, calculated free testosterone, LH, FSH, prolactin, and full blood count alongside the standard nutritional and thyroid markers. This is most useful when there is an existing fertility concern or unexplained subfertility.
Ready to book?
Same-day appointments at 134 Harley Street usually available. A GMC-registered doctor designs your panel and confirms the price before booking.