A new observational study has linked caffeine consumption during pregnancy with a number of potential complications, suggesting that it may not be safe to consume the common stimulant in any quantity while pregnant. This surprising — and controversial — finding is contrary to current medical advice, which is that while pregnant when can generally consume caffeine, they should cap the quantity to no more than 200mg daily.
The new study is itself an analysis of existing research; it was recently published in the BMJ Evidence-Based Medicine journal. The findings suggest that women planning to conceive, as well as pregnant women, should avoid all caffeine because of the potential risk of negative effects on the pregnancy.
Caffeine is a commonly consumed stimulant that can be tricky to avoid; it is found in small quantities in chocolate and some teas, as well as in higher levels in coffee and many soda beverages, among other things. Current health standards advise women to limit their caffeine intake during pregnancy to the equivalent of around two cups of coffee daily.
The new analysis is contrary to this, focusing on 48 original observational studies pulled from more than 1,000 published papers. The research is spread over a duration of around two decades and indicates a link between caffeine consumption and negative pregnancy outcomes, including low birth weight, miscarriage, stillbirth, small size, and more.
In his analysis, Reykjavik University Professor Jack James notes that because this is an observational study, it can’t state whether caffeine is the cause of these observed negative outcomes. Other factors could potentially influence the outcomes, such as expecting mothers under-estimating how much caffeine they consumed or other lifestyle factors like smoking.
Some of the studies, James notes, linked any level of caffeine consumption with negative pregnancy outcomes, which the researcher says ‘supports likely causation rather than mere association.’ Having concluded that the link between caffeine and negative outcomes has ‘substantial cumulative evidence,’ he states that there should be a ‘radical revision’ in caffeine limit recommendations given to expecting mothers.
The conclusion has proven controversial among some experts, however. Royal College of Obstetricians and Gynaecologists spokesperson Dr. Daghni Rajasingham said in a statement:
The findings of this study add to the large body of evidence that supports limited caffeine intake during pregnancy, but pregnant women do not need to completely cut out caffeine, as this paper suggests.
As the study notes, high levels of caffeine during pregnancy can lead to miscarriage and babies having a low birth weight and may lead to excess weight gain in the child’s early years, which can increase the risk of health problems later in life. However, as other – and potentially more reliable – research has found, pregnant women do not need to cut caffeine out entirely because these risks are extremely small, even if the recommended caffeine limits are exceeded.
The Royal College of Obstetricians and Gynaecologists’ advise to limit caffeine intake to 200 milligrams (mg) per day – the equivalent to two cups of instant coffee – still stands. This paper does not supersede all the other evidence that has found that a limited intake of caffeine is safe for the majority of pregnant women.