You’ve probably heard that you should limit the caffeine in your diet during pregnancy. Caffeine is a legal and unregulated stimulant, known for its ability to increase our alertness. It’s found in the fruit, leaves and seeds of certain plants. We mainly consume it in infusions extracted from the seeds of the coffee plant and the leaves of the tea bush, as well as other foods and drinks made from the kola nut. You may be wondering why caffeine is a problem, and which foods and drinks are OK to include. This article aims to provide the answers to your caffeine-related questions.
Why should caffeine be limited during pregnancy?
Caffeine is metabolised slower during pregnancy and can cross the placenta from mum’s blood into the baby‘s bloodstream. Developing babies lack the enzymes to break down caffeine, so the caffeine stays in their bodies for longer, causing potentially detrimental effects.
Research shows that women who drink too much caffeine during pregnancy have a higher risk of delivering a low birth-weight baby. One study showed that women who consumed over 200mg of caffeine a day had 20-60% higher risks of having a low birth-weight baby. Low birth-weight babies are more at risk of becoming obese and developing chronic health conditions, such as diabetes and heart disease in later life. For these reasons, the Department of Health recommends that caffeine should be limited to 200mg per day during pregnancy.
Guidance on how much caffeine is safe
You can use the table below to check if you’re having a safe intake of caffeine:
Food / drink
Amount of caffeine (mg)
Coffee* - 200ml mug filter
Coffee* - 200ml mug instant
Tea - 200ml mug
Cola - regular or diet 330 ml can
Cola - regular or diet 500ml bottle
Dr Pepper & Pepsi Max - 500ml bottle
Energy drinks** e.g. Monster, Red Bull, Irn Bru, Lucozade Alert - 240ml can
Hot chocolate - 200ml mug
Up to 10
Chocolate milkshake – 250ml glass
Chocolate - 50g bar plain
Up to 50
Chocolate - 50g bar milk
Up to 25
* Café-style coffees, e.g. lattes and espressos are likely to contain more caffeine than this
**Take particular care with energy drinks, and preferably avoid them because some brands contain much more caffeine than this
An example of a safe daily level of caffeine would include 1 mug of instant coffee, 1 mug of tea and a 50g bar of milk chocolate. Take care with cold and flu remedies, as many of these contain caffeine. Check with your pharmacist or doctor first.
As well as caffeine, tea and coffee contain ‘tannins’, chemicals which bind to dietary iron, and can therefore reduce the body's absorption of iron and other nutrients. Drinking tea and coffee at mealtimes can mean less iron is absorbed by the body. As pregnant women are more susceptible to anaemia, consider avoiding tea and coffee at mealtimes and drink it in between meals instead.
I’m trying for a baby - should I limit my caffeine too?
I’ve just had a baby - is it safe to increase my caffeine intake again?
It you’re breastfeeding, you may find that consuming drinks containing caffeine may affect your baby, causing them to be wakeful, irritable or restless. There’s no UK guideline on what’s a safe amount for breastfeeding, but in the US, the limit is 300mg. It’s best to continue limiting caffeine if you notice that it’s affecting your baby.
Sengpiel et al (2013) Maternal caffeine intake during pregnancy is associated with birth weight but not with gestational length: results from a large prospective observational cohort study. BMC Med. 11:42.
The American College of Obstetricians and Gynecologists (2010) ACOG Committee Opinion No. 462: Moderate Caffeine Consumption During Pregnancy. Obstet Gynecol. 116(2 Pt 1):467-8.
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