5 Key Fertility Blood Tests For Nutrition
If you’ve been trying to conceive for some time now, I understand how disheartening and exhausting that can feel. Sometimes, the answer isn’t just about “trying harder”. It’s about uncovering underlying factors that haven’t yet been explored.
One often-overlooked area is nutrition-related blood testing. These aren’t always included in standard fertility work-ups, but they can provide powerful insights into nutrient or hormone imbalances that may be quietly affecting your ability to conceive or maintain a pregnancy.
In this blog, I’m going to walk you through the five key blood tests I often recommend inside my signature Mastering Egg Health Program™.
1. Vitamin D
Vitamin D plays a vital role in reproductive health, including egg development and implantation.
Research shows that women undergoing IVF were significantly more likely to achieve a live birth when their vitamin D levels were above 75 nmol/L. Higher than the typical normal range. Seasonal variations in fertility outcomes have also been linked to differences in vitamin D status, with higher success rates in sunnier regions.
However, too much vitamin D can be harmful. This is why testing before starting or adjusting supplements is essential.
2. Folate
Folate is crucial for DNA synthesis and cell division, both of which are fundamental in the earliest stages of conception.
Studies have found that women with higher folate levels had improved fertilisation rates and embryo quality during assisted reproduction.
But more isn’t always better. Excessive synthetic folic acid, especially in women with specific MTHFR gene variants, can lead to unmetabolised folate in the bloodstream, which may have adverse health effects.
The right type (folic acid vs. activated folate) and dose should always be personalised based on your blood test results and medical history.
3. Ferritin
Ferritin is a marker of your iron stores, which are critical for oxygen delivery to reproductive tissues and for creating a supportive uterine environment.
Evidence suggests that a ferritin level of at least 60 μg/L is linked with higher fertility and lower miscarriage risk. One study even found that raising ferritin to around 80 µg/L in women with low iron significantly improved live pregnancy rates and reduced pregnancy loss.
At the same time, excessive iron may increase oxidative stress, which can negatively impact egg quality. Again, highlighting why testing is key before supplementing.
4. Zinc
Zinc is a trace mineral involved in hundreds of enzymatic reactions, including DNA synthesis, cellular repair, and embryo development.
While much of the research has focused on zinc’s role in male fertility, women need healthy zinc levels too. Deficiency may impair cell division and reduce reproductive efficiency.
Ensuring adequate zinc through diet or supplementation (guided by testing) can support optimal egg and embryo development.
5. Thyroid-Stimulating Hormone (TSH)
TSH controls thyroid function, which directly impacts ovulation, reproductive hormones, and early pregnancy maintenance.
For women planning pregnancy, the American Society for Reproductive Medicine (ASRM) recommends aiming for a TSH of 2.5 mIU/L or lower. Even mildly elevated TSH within the general “normal” range has been associated with reduced fertility and higher miscarriage risk.
However, not all research agrees. Some studies argue that a strict preconception TSH cutoff of 2.5 mIU/L may be unnecessary, and that maintaining TSH within the overall reference range is sufficient for many women.
If your TSH is raised, further testing (free T4, free T3, and thyroid antibodies) can help determine whether thyroid support is needed before trying to conceive.
Bottom Line
- Nutrition-related blood tests can provide essential insight into your fertility health.
- Getting the proper fertility blood tests done helps determine whether you need specific nutrition or supplements, instead of relying on guesswork or taking more than your body needs.
Working with a fertility dietitian can ensure your lab results are interpreted correctly and translated into a safe, personalised supplement plan to support your fertility journey. Learn more about our express supplement review now.
