5 Key Nutrition Tests to Include in Your Fertility Blood Work
If you’ve been eating better, tracking your cycle, and taking supplements, but still feel like nothing is working, you’re not alone.
One of the biggest mistakes I see is guessing your way through supplements without checking the right fertility blood work first.
Fertility is complex. And taking the wrong supplements, or missing key deficiencies, can delay your journey and leave you feeling more confused than ever.
In this post, I’m sharing the five essential nutrition tests I recommend checking in your fertility blood work before you start or change your fertility supplement routine.
1. Vitamin D: A Reproductive Powerhouse
Most people know vitamin D supports bone health, but it also plays a significant role in fertility. Vitamin D helps regulate reproductive hormones, supports follicle growth, and may even improve the uterine lining’s ability to support implantation.
A comprehensive study involving 3,711 women undergoing in vitro fertilisation (IVF) examined whether vitamin D levels affect fertility outcomes. Women were grouped by their vitamin D status:
- Sufficient (≥75 nmol/L)
- Insufficient (52.5–72.5 nmol/L)
- Deficient (<50 nmol/L)
Women with sufficient vitamin D had:
- 43% higher odds of becoming pregnant
- 29% higher odds of carrying the pregnancy further
- 74% higher odds of giving birth compared to those with low levels
This study suggests that women with higher vitamin D levels (above 75 nmol/L) had better IVF outcomes.
Even in sunny countries, deficiency is common due to indoor lifestyles, sunscreen use, and skin coverage. Test your vitamin D and supplement based on your levels for the best results under a fertility dietitian’s guidance.
2. Ferritin: More Than Just Iron
Ferritin is the marker we use to assess stored iron, and it plays a crucial role in supporting ovulation, egg health and a healthy uterine lining.
In one study of 292 women with infertility and low ferritin (<30 µg/L), it was found that after receiving iron infusions, raising ferritin levels from 16 to 80 µg/L doubled the live birth rate and cut miscarriage risk in half. That’s a significant impact from a small but mighty nutrient.
Prenatal vitamins often contain just enough iron to maintain levels, not correct deficiencies. That’s why a personalised interpretation of your fertility blood work is essential before supplementing, including evaluating your nutritional status.
3. Folate: Not All Forms Are Equal
Folate is essential for DNA synthesis, egg maturation, and reducing the risk of neural tube defects. However, not all forms of folate are equally absorbed, especially for those with MTHFR gene variants.
One IVF study found that women with the highest blood folate levels had a 62% higher chance of live birth than those with the lowest level (<37.6 nmol/L). Even better results in nearly double the live birth rate (1.92 times higher) were seen when both folate and B12 levels were in optimal ranges.
The best way to check folate status is via serum or RBC folate (a longer-term marker). This is critical to your fertility blood work, especially if you’re unsure whether your supplement contains the proper form or dose.
4. Homocysteine: The Missing Link
Homocysteine is an inflammatory marker rarely included in standard fertility blood panels, but it should be. Elevated levels have been linked to higher miscarriage risk, poor egg quality, and even earlier reproductive aging.
Research shows women with unexplained infertility or recurrent pregnancy loss often have significantly higher homocysteine levels (>15 µmol/L) than those with normal fertility.
In IVF, lower follicular fluid homocysteine level (9.6 ± 2.02 µmol/L) has been associated with greater chances of pregnancy, even when embryo quality appears similar. These findings suggest that lower homocysteine in the follicular fluid is strongly associated with higher chances of clinical pregnancy.
Higher homocysteine concentration has also been associated with recurrent pregnancy loss, likely because it can impair blood vessel health and increase oxidative stress, both of which may disrupt implantation or early embryo development.
The good news? Targeted supplementation with folate, B12, and B6 can help reduce homocysteine levels, but the correct form and dose matter. That’s why working with a fertility dietitian is worth assessing your blood work and developing a personalised plan that supports your unique needs.
5. Zinc: Small Mineral, Big Fertility Impact
Zinc is crucial in female reproduction, contributing to oocyte development, hormonal regulation (including FSH and LH synthesis), fertilisation, and early embryo growth. It’s essential for healthy egg maturation, protecting DNA, and supporting early embryo development after fertilisation.
If you’ve been on the Pill, follow a vegetarian diet, experience gut issues, or have chronic stress, you could be at risk of low zinc.
While serum zinc isn’t the most precise way to assess zinc levels, it’s a clear sign that your body may be deficient if it comes back low. Correcting this is essential, but high-dose zinc can throw off the balance of other minerals like copper and iron, so it’s best to personalise your dosage based on your complete nutrient profile.
Bottom Line
- Taking supplements without understanding your unique needs can set you back.
- Proper fertility blood work to check nutrition status is the first step in my clinic before recommending any supplement strategy.
- If you’re ready to take that step, book your Express Supplement Review, where I’ll go through your blood test results and current supplements to create a plan tailored to your body.
