Caffeine in pregnancy: How much is too much?
By Annemarie Aburrow RD
By Annemarie Aburrow RD
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.
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.
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||140|
|Coffee* – 200ml mug instant||100|
|Tea – 200ml mug||75|
|Cola – regular or diet 330 ml can||40|
|Cola – regular or diet 500ml bottle||60|
|Dr Pepper & Pepsi Max – 500ml bottle||95|
|Energy drinks** e.g. Monster, Red Bull, Irn Bru, Lucozade Alert – 240ml can||80-100|
|Hot chocolate – 200ml mug||Up to 10|
|Chocolate milkshake – 250ml glass||5-8|
|Chocolate – 50g bar plain||Up to 50|
|Chocolate – 50g bar milk||Up to 25|
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.
Consuming too much caffeine may reduce your fertility and may increase risk of miscarriage. Therefore, it’s best to limit your intake to 200mg of caffeine a day when you‘re trying for a baby too. In fact, pre-conception is a great time to evaluate your caffeine intake and cut down in preparation for pregnancy.
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.
British Nutrition Foundation (2013) BNF Taskforce Report - Nutrition and development: short and long term consequences for health.
MAFF (1998). MAFF UK - Survey of caffeine and other methylxanthines in energy drinks and other caffeine-containing products (Accessed September 2013). Food Surveillance Information Sheet.
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.