One in four NZ women will experience a miscarriage at some point during their life, with rates similar in other OECD countries. Going through a miscarriage can be devastating, often left with no explanation of the cause. It’s not until you have three miscarriages (including biochemical) that you’re diagnosed with recurrent miscarriage (RM) and can have publicly funded medical investigations into the cause (in NZ at least).
Miscarriages occur for a range of reasons; the main underlying cause being too many embryonic chromosomes in dividing cells called aneuploidy, aka “genetic instability”. There are multiple factors which impact this genetic instability, many of which are outside our control; cue age.
But did you know that some of the foods we eat, and things we’re exposed to in the environment can impact our risk? Now, this article is not designed to trigger feelings of guilt. I’ve written this with the intention of informing the reader so they’re better armed to help their odds of having a healthy baby.
So, let me guide you through some of the key nutrition and lifestyle factors which evidence links to miscarriage, so you can take back some control and optimize your chances as best you can.
Top foods and nutrients to include:
The benefits of eating fruit have been long known and drummed into us since we were children. However, a 2001 Milan study looking into dietary factors and spontaneous abortion found that eating just two pieces of fruit a day can reduce your chances of miscarriage by up to a whopping 70%! What’s alarming, is a recent NZ Ministry of Health survey found that only 59% of women were eating the recommended two servings of fruit each day.
Folic Acid (Vitamin B9)
Folic Acid (Vitamin B9), (which won’t come as a surprise) is essential for the development and formation of a baby’s neural tube. Remember, this is the structure that goes on to form the spinal cord and brain. Women planning a pregnancy are recommended to eat folate rich foods in addition to taking a folic acid supplement for a MINIMUM of one month prior to conception and for the first three months of pregnancy. However, with the Oral Contraceptive Pill’s (OCP) ability to deplete nutrient absorption, longer supplementation would be a very good idea.
Higher intakes of folate reduces the risk of neural tube defects (NTDs) and subsequently reduces the risk of spontaneous miscarriages. Some women will require higher amounts of Folic Acid to prevent NTDs, so be sure to read my blog on Folate and check with your GP or Fertility Dietitian to see if you need a higher dose.
MTHFR Gene Mutation
MTHFR gene mutation could potentially cause recurring miscarriage. Taking high doses of Folic Acid in these people can be problematic. However, even with a MTHFR mutation, a small amount of Folic Acid can still be converting to methylated folate.
So, whilst for those with the gene mutation, it would be beneficial to take methylated folate, evidence to date does support taking Folic Acid to prevent NTDs. This is a confusing area, not well understand by many. My advice is to check with your Fertility or Prenatal Dietitian to ensure your supplementation is personally tailored baed on your risk factors.
Omega 3 Fatty Acids
Omega 3 Fatty Acids, namely the essential marine sources, EPA and DHA are anti-inflammatory, essential for reproductive health. Omega 3 fatty acid supplementation has been positively associated with increased uterine blood supporting a healthy pregnancy and reducing the risk of a miscarriage.
However, not all Omega 3 supplements are the same. They’re prone to oxidation, which means they have a short shelf life and not all brands are equal in terms of quality. A recently published New Zealand study found that the majority of products tested exceeded the recommended level of oxidation markers. For this reason, always seek expert advice as to which supplement and how much is right for you.
Niacin (Vitamin B3)
Niacin (aka vitamin B3) is an important nutrient for the healthy growth and development of a baby during pregnancy. It’s an essential nutrient, meaning our bodies can’t make it on its own. There’s been recent hype over this vitamin, with a 2020 study in mice showing that niacin may play an important role in preventing some miscarriages and birth defects.
However, before you go reaching for those niacin supplements, more research is needed in humans before we can make safe and conclusive recommendations for supplementation. Until then, my top three niacin rich foods include pork, chicken and brown rice.
This fat soluble vitamin is produced when sunlight hits your skin and is important for the absorption of calcium. Vit D is thought to play roles all throughout the body in many organs. Interestingly, preconception serum levels of Vitamin D which are >75 nmol/L have been associated with a higher chance of pregnancy and lower risk of miscarriage.
You can increase your serum Vitamin D levels by enjoying some sunshine. And some foods will give you small amounts of Vit D, such as salmon, tuna or eggs. But it’s difficult to get enough Vit D from food alone, and in winter, particularly if you live south of Wellington due to NZ’s latitude. This is why I always check my clients Vit D levels and ensure they’re getting the right dose of Vit D for optimal levels to prevent miscarriage.
Things to avoid:
This daily jump starter is one of the most researched foods related to pregnancy outcomes. If you are pregnant you are encouraged to limit your caffeine intake to <200mg / day (2 cups of coffee), since excess amounts are known to increase the risk of miscarriage.
So why is that? This is because caffeine is a stimulant that can cross the placental barrier and reduce placental blood flow by increasing levels of hormones called catecholamines. During pregnancy babies also haven’t developed the ability to metabolise caffeine as quickly as a pregnant mother, therefore it also stays in their systems longer.
While on the other hand, there is no known safe level of alcohol consumption during pregnancy and its best avoided if you’re pregnant or trying to get pregnant. Because research clearly shows an increased risk of miscarriage with drinking more than 4 alcoholic drinks per week.
Beyond the risk of miscarriage, new research published looking at the long-term effects of consuming alcohol during pregnancy shows that babies who experience ongoing and excessive pre-natal exposure to alcohol develop structural abnormalities in their brain and other key organs (i.e. kidneys).
These children go on to experience higher rates of cognitive and behavioural issues and are at a greater risk of chronic diseases later in life such as chronic kidney disease. So while previous advice may have alluded to the safe consumption of 1-2 drinks. My advice? Just don’t risk it!
Bisphenol A (BPA)
BPA are those well-known plastics which are known to impact fertility. A 2014 study published in Fertility and Sterility, showed that serum levels of BPA were raised among the miscarriage group. Those with the highest amount versus the lowest amount had 83% increased risk of miscarriage.
It’s hard to avoid BPA completely, but these are some of the most common sources to avoid: plastics bottles, plastic food containers, plastic food packaging and plastic kettles. Other sources include eftpos receipts, some coffee capsules, rotisserie chicken packets and linings of tinned food. Keep an eye out for the term “BPA free”. If it doesn’t mention BPA, consider it a culprit.
Common metals such as mercury, lead and cadmium are found in deep sea fish such as mackerel, shark and swordfish. Did you know that a common fish used at fish and chip shops is shark? Pregnant women are recommended to avoid these as heavy metals can cross the placental barrier and cause permanent damage to a fetus’ organs. Unfortunately, it’s not just large deep sea fish which are problematic. Have you read my BLOG on Collagen Supplements? I recommend working with a Fertility Dietitian to ensure you’re excluding possible sources of heavy metals from foods as well as supplements.
Listeria risk foods
Listeria is a common foodborne bacterium which can also cross the placental barrier and increase the risk of spontaneous miscarriage. And the frustrating thing about Listeria is that sometimes women don’t even know they’re affected. Foods such as deli meats, unpasteurised milk, soft cheeses and cooked then chilled foods are considered high risk for listeriosis and best avoided in the lead up to an embryo transfer and throughout pregnancy.
Do you have an underlying medical condition?
There are three main nutrition related medical conditions which can increase your risk of miscarriage worth considering.
Coeliac disease (CD) is basically an allergy to gluten. Having undiagnosed and/or untreated coeliac disease can increase your risk of miscarriage by nine-fold. This is through nutritional deficiencies and an autoimmune reaction which can damage the placenta and embryo. If you’ve never been screened, then an antibody screen via blood test is recommended. Speak to your GP or Fertility Specialist about this. Remember though, if you’re following a diet which is low in gluten, you’ll need to undergo a gluten challenge, otherwise you risk a false negative. Discuss this with your Dietitian!
Also known as an under-active thyroid, occurs when the body doesn’t make enough of the thyroid hormones. Approximately 1-2% of women of reproductive age suffer from hypothyroidism; if left undiagnosed it can increase your risk of miscarriage. Therefore, it is important to talk to your GP and ensure you receive comprehensive pre-conception checks and care.
Unfortunately, obesity is a known risk factor for miscarriage. A 2008 Meta-Analysis showed women who are obese have a 38% risk of miscarrying compared to 13% in those with a healthy weight. The good news is that achieving just 5-10% of body weight can have huge clinical benefits, so if you’re looking for support with achieving weight loss goals, seeing a Fertility Dietitian can help fast track results.
Swimmers and Miscarriage:
Whilst the swimmers might have been tested, for things like count and morphology, high levels of DNA fragmentation in semen can be a contributing factor to ongoing infertility. Interestingly, researchers Jayasena et al. found that male partners (n=50) of women who had experienced recurrent miscarriage (RM) had two-fold higher levels of sperm DNA fragmentation and markedly increased levels of oxidative stress in their semen.
DNA fragmentation is not a black and white test result. If there are high levels of damaged DNA, then it’s time for the baby Daddy to address lifestyle habits and his nutrition. If you’re struggling with recurrent miscarriage and haven’t had this tested, then I strongly recommend asking your Fertility Doctor about this. And reach out to a Fertility Dietitian, because we specialise in modifying nutrition and lifestyle to reduce oxidative stress and subsequent DNA fragmentation.
Several studies have shown that male obesity negatively impacts sperm quality and quantity, the long-term health outcomes and disease risks of their children, as well as the risk of miscarriages. Obesity and health conditions which commonly go along with it increases the oxidative stress in the body. Luckily, moderate levels of paternal weight loss can increase sperm quality and quantity, as well as significantly reducing the risk of miscarriage and long-term health conditions.
What’s most important, is correct vitamin and micronutrient supplementation on top of a Mediterranean diet. Couple this with reduced exposure to toxins and chemicals and you can increase sperm quality and quantity; as well as significantly reducing the risk of miscarriage and long-term health conditions.
Going through a miscarriage is absolutely heart-breaking, especially when you’re left with more questions than answers. It’s completely understandable to feel anxious about the outcome of future pregnancies. If this sounds like something you’re struggling with, then I’d love to help you. Click here to book a Free discovery call with me and learn about my Fertility Wellness Program.