A pre-conception blood test is one of the highest-leverage tests you can take. Some nutrient deficiencies (particularly iron, B12, folate, vitamin D) and untreated thyroid issues can affect both fertility and early pregnancy outcomes. Catching them before pregnancy is the easiest time to fix them.
Hormones that matter for fertility
FSH, LH and oestradiol on day 3 of cycle. Progesterone on day 21 to confirm ovulation. AMH for ovarian reserve. TSH and free T4 because thyroid issues are common and affect fertility.
Nutrients to check before pregnancy
Iron and ferritin (anaemia common in women of reproductive age). Vitamin B12 and folate (both critical in early pregnancy for neural tube development). Vitamin D (often low in UK winters).
What about male partners?
Sperm analysis is the gold standard and requires specialist testing. Chxhealth offers male hormone testing (testosterone, SHBG) which is a useful complement but does not replace a semen analysis.
Timing your tests
Day 3 of cycle for the reproductive hormone baseline. AMH and thyroid any day. Best done 3 to 6 months before trying to conceive so there is time to address any findings. Chxhealth is a biomarker and genetic data provider. We do not diagnose, treat or prescribe. Our service supports your wellbeing journey alongside your healthcare professional.
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Frequently asked questions
When should I start pre-conception testing?
3 to 6 months before you start trying. This gives time to address any nutrient gaps or thyroid issues identified.
Should I take folate even if my levels are normal?
NHS guidance recommends 400 micrograms folic acid daily from before conception through the first 12 weeks of pregnancy regardless of baseline levels. Speak to your GP for individual guidance.
About this article. Educational content. Chxhealth is a biomarker and genetic data provider. We do not diagnose, treat or prescribe. Our service supports your wellbeing journey alongside your healthcare professional. For medical advice about your health or results, please speak to a qualified clinician.
