Key nutrition blood tests for fertility

Today, we’re going to spill the tea on nutritional blood tests for fertility.  Why? Because nutrition is literally the fuel for our body and is often dismissed when investigations are done for infertility.  


When my clients come to see me, despite having a number of investigations done to investigate the cause of their infertility, some key nutrition bloods are often missing.  And when they are not, my clients have been told that their blood results are within the normal range.  The problem with this is that the reference range for ‘normal’ is often very big and so even if you are technically within the normal range, it is often not in the ideal range for conception.

What blood tests should I ask for?

So, here are some of the tests I request from the GP and that you should also ask to have drawn:

Vitamin D

Unless you have been living under a rock, we have all heard about the importance of vitamin D for our bone health.  But did you know that the benefits are not limited here and also extend to sperm and egg health? One Italian study showed that in women undergoing IVF, having sufficient levels of vitamin D made them more likely to produce higher quality eggs, thus increasing the chances of conceiving.  When it comes to male fertility, some studies have shown that vitamin D improves sperm motility and helps to control hormone production.

In my experience, many of my male and female clients are well below the sufficient range which is why it is so important to get tested.  For those who are within the normal range, a lot of them are borderline sufficient and since many fertility clinics prefer vitamin D levels to be between 75-100, I often create a specialised supplement regime for my clients to help raise the levels to the target amount.


There are multiple blood tests to test for iron levels in the body, but one of the key tests which are often overlooked is ferritin.  This is an iron storage protein that looks at your overall iron stores, rather than just looking at what is in the blood at the point of the blood test. One job of iron is to circulate oxygen around the body and this is especially important in fertility since women need a healthy blood and oxygen supply to the ovaries and uterus.  

Most fertility specialists would want this level to be above 50ug/L and in my experience, most women are well below this target. Depending on the level, I sometimes advise on an additional iron supplement or educate clients on how to improve iron levels through diet strategies.

Coeliac disease

If you have been struggling to conceive for over a year or have had 2 or more miscarriages, then it is worth both partners having a coeliac screen.  Coeliac disease is an autoimmune disease whereby the immune system destroys the villi of the small bowel. This is due to a negative reaction to gluten which is a protein found in certain grains.

If left untreated and undiagnosed, it means your body is unable to absorb nutrients efficiently leading to poor sperm quality, poor egg quality, difficulty in conceiving and reducing the ability to carry the pregnancy to term. 

Vitamin B12

Deficiencies in B12 can lead to blood clotting abnormalities which can subsequently increase the risk of repeated miscarriage and potentially inhibit an embryo from implanting in the uterus after fertilisation. This is a vitamin that often gets depleted if you are on metformin or proton pump inhibitors such as omeprazole.  In addition, vegetarians, vegans and those following a largely plant-based diet will be at high risk of vitamin B12 deficiency.

Wondering about your own lab results? If you need nutrition support in your fertility journey and would like to develop your own personalized fertility protocol you’re welcome to book in for a FREE discovery call where we can discuss how nutrition may be able to optimise your fertility.

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

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London SW14 & E18
Written by Rania Salman, Registered Dietitian, PgDip (Merit), BSc (Honours), MBDA
London SW14 & E18

Rania Salman is a trained dietitian who uses an evidence-based approach to support you in reaching your goals. Her areas of expertise include Fertility, PCOS, weight loss/gain in addition to general health and wellbeing. She has worked in some of the most well-known NHS trusts, in addition to working for the private sector.

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