Experts believe caffeine during pregnancy can negatively impact pregnancy and beyond. But is there any amount of caffeine that is safe? Or is it better to eliminate your caffeine intake completely? 

Caffeine, not coffee 

‍When people think of caffeine consumption, their minds spring to drinking cups of coffee, but caffeine is in other foods and drinks too. You will find caffeine in energy drinks, teas, chocolate, cups of cocoa, soft drinks and even over the counter medications. Cold and flu medicines or paracetamol often include caffeine, so opt for the version without caffeine where possible. But the thing that most people struggle with is to give up their morning cup of coffee. 

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Mug of black coffee and coffee granuals

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Skinny latte, americano or espresso? Many people drink coffee every day without giving it a second thought. Yet, this innocent beverage could be impacting your fertility and chances of successful IVF treatment.  

Given it’s a stimulant, caffeine can be a hard habit to quit—even though some pregnant women find it causes heartburn. Whatever your taste in coffee, healthcare professionals advise you to reduce your coffee intake before, during and after pregnancy because high levels of caffeine can cause an increased risk of infertility and pregnancy complications. 

Remember to check the label first to see what the caffeine content of your foods and drinks is.  

How much caffeine is too much? 

According to guidelines, it is recommended that your caffeine consumption does not exceed 200 milligrams per day, which is equivalent to about 2 cups of instant coffee.  

Knowing how much caffeine is in the products you buy can be a challenge. Below is a caffeine calculator, as referenced from the NHS. There are approximately: 

  • 100 mg of caffeine in a mug of instant coffee 
  • 140 mg of caffeine in a mug of filter coffee 
  • 75 mg of caffeine in a mug of tea (regular or green tea) 
  • 34 mg of caffeine in a 12oz can of regular or diet cola 
  • 80 mg of caffeine in 250 ml cans of energy drinks 
  • less than 25 mg of caffeine in 50 g of a plain dark chocolate bar 
  • less than 10 mg of caffeine in 50 g of a plain milk chocolate bar. 

The amount of caffeine you have can be difficult to measure as it can vary from product to product. This is particularly true of herbal tea, where the amount can vary as much between the types of tea as it can between the different brands. Check the ingredients of the food you eat in case they include coffee and chocolate. We are more aware of our caffeine consumption in beverages, yet we sometimes forget about caffeine hiding in foods. It is best  to avoid caffeinated products where possible and substitute it by drink water or soft drinks that don’t contain caffeine. 

Does caffeine affect IVF and IVF implantation?  

The evidence from studies varies, with some showing no change and others showing a negative impact on fertility. Many women drink coffee during pregnancy without any evident adverse effects for them or their children. A study published in 2018 found no effect of moderate coffee intake by women, men, or the couple on oocyte quality and success rate after IVF procedures. But, the authors of the research in the BMJ concluded that women who are trying to conceive or already expecting a baby should avoid caffeine altogether. There’s ‘no safe level’ according to their research. 

Other experts disagree with this drastic approach. They point out that the risks from caffeine are still extremely small, that the data is based on women recalling how much they consumed, and that other factors that go with high caffeine intake could have had an impact, such as smoking or drinking alcohol.  

The official line from the NHS is to limit the amount of caffeine consumed by not exceeding more than 200 mg per day – the equivalent of two cups of moderate-strength coffee. This is also the advice from other health organisations, including the Royal College of Obstetricians and Gynaecologists (RCOG). 

However, this may change if more substantial evidence emerges. A few months after the BMJ research was published, scientists reported a 27 % increase in stillbirth risk for each 100 mg of caffeine consumed. The experts from the charity Tommy’s research centre at the University of Manchester studied more than 1,000 mothers across UK hospitals. They found energy drinks posed the most dangers, followed by instant coffee and cola. In response, the RCOG said they would support a review of the current 200 mg limit.

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Energy drink in a can

This recommendation is based on a comprehensive review of several dozen existing studies published over two decades. Published in the British Medical Journal (BMJ), researchers in Iceland found robust evidence that caffeine consumption was linked with adverse effects in pregnancy, including miscarriage, stillbirth and low birth weight. They identified an association with children being overweight, which creates risks for them in adulthood, and with leukaemia in childhood.  

Why does caffeine affect fertility?  

Why caffeine poses a risk to fertility and unborn babies is not entirely understood. It’s believed that a baby cannot process caffeine effectively like adults. Adults can break down caffeine via the liver, but babies developing in the womb don’t have this ability. When the drug crosses the placenta, the tiny foetus is exposed to concentrations similar to those found in the mother, which the baby struggles to deal with. There’s also some research showing that natural stimulants may decrease blood flow to the placenta.   

Healthcare professionals advise you to reduce your coffee intake before, during and after pregnancy because high levels of caffeine can cause an increased risk of infertility and pregnancy complications. Experts believe that caffeine may negatively impact pregnancy, and while there is a link between low birth weight and caffeine consumption, there is no link to preterm birth.   

As you can see, there is no conclusive evidence and for this reason, so it’s best in the least to follow the current guidelines. You may want to adjust your nutrition and fertility diet while you are trying to get pregnant. If you are struggling with curbing your caffeine intake as you embark on your IVF journey, then do seek advice from your fertility specialist. 

The IVF Network provides help to members and connects you with the best experts to offer advise on your fertility issues.