Introduction
Chances are when you started trying to get pregnant, your doctor told you to just take any prenatal (or just folate) but then Instagram, TikTok, and the fertility forums are full of complicated supplement routines for fertility. We spoke with fertility dietitian, Amara Lindenmayer, whose job is to look at the science and help figure out what’s truly worth the time and money (and what might actually cause more harm than good!).
How exactly can a supplement backfire?
Firstly, even the nutrients we need while trying to conceive are only good for us in certain quantities. Take iodine, for example. It’s critical for thyroid function and reproductive hormone balance and many guidelines suggested it is taken while trying to conceive and during pregnancy. However, iodine is also toxic at high doses. Too much can throw off thyroid function, which can interfere with fertility and even lead to serious health risks. I’ve had clients unknowingly taking extremely unsafe doses just through one pill.
Supplement regulations (or the lack of)
Unfortunately, in most countries, supplements aren’t well regulated. That means manufacturers can legally sell extremely high doses, and no one is required to test what’s actually inside the bottle. So even if you’re taking what seems like the correct dose, the amount on the label might not reflect what you’re actually getting. It could be more, less, or none at all!
That’s why it is always recommended to choose third-party tested supplements. These are independently verified to contain what they say they do, and to be free from harmful contaminants. This matters because research has found supplements contaminated with everything from pharmaceuticals to bacteria and heavy metals.
One Canadian study tested 51 prenatal supplements and found that 40% had lead levels above safe thresholds. Others contained arsenic and thallium. And similar findings have been reported in other countries too. So yes, third-party testing matters. But even that’s not the whole picture.
Personalised approach
Just because a supplement is clean and accurately labelled doesn’t mean it’s right for you. Supplements should be chosen based on your individual needs. What’s right for you will depend on your dietary intake, blood test results, medical history, and more. This is where personalised advice from a fertility dietitian comes in.
Then there are nutrients that can support specific groups. For example, certain supplements may help people with PCOS, thyroid conditions, or diagnosed nutrient deficiencies. And then there’s the issue of nutrient interactions. For example, iron and calcium can interfere with each other’s absorption if taken together. This is why a personalised approach matters so much. Your supplement regime should be tailored to your body and your needs.
And to be clear—this isn’t a call to stop taking folate. The evidence supporting folic acid in reducing neural tube defects is robust and well-established. Just make sure you’re using a third-party tested product, and get your overall supplement plan reviewed by a fertility or pregnancy dietitian.
What to look for in a supplement
- Third-party testing: Look for certification from trusted bodies (e.g. TGA, USP, NSF). This helps ensure quality and safety.
- Personalisation: Your supplement needs should be based on your diet, lab results, and health history. Seek advice from a qualified practitioner.
- Folate: The most important and well researched fertility nutrient, this one is non-negotiable while trying to conceive and in early pregnancy.
The right supplements can support your journey and help you have the healthiest pregnancy possible, but only when chosen with care, based on evidence, and tailored to your individual needs. If you’re not sure what’s right for you, speak with a fertility dietitian who can help you assess your needs and create a supplement plan that supports your fertility, not undermines it.
About the Author
Amara is an Australian fertility dietitian based in Singapore, with over a decade of experience living and working in Asia. She specialises in evidence-based nutrition strategies to support egg quality, ovulation, hormonal health and implantation—helping you take charge of your fertility with a clear plan. She is available for consults focused on fertility, pregnancy, and postpartum nutrition.
