What’s the truth about pregnancy and coffee?

Pregnant women should cut out caffeine entirely during the first eight weeks of pregnancy to minimise the risk of losing their baby, researchers suggested this week.

However, NHS guidelines currently recommend limiting caffeine intake to 200mg a day while pregnant (the equivalent of two cups of instant coffee – filter coffee contains more caffeine, more on which later), rather than cutting it out entirely.

Some experts say more research is needed before expectant mothers jump to conclusions (and switch to decaff). 

So, what’s the truth about caffeine and pregnancy? The coffee debate is a thorny one to navigate at the best of times, not least when the health of an unborn child is at stake.

The health benefits versus the disadvantages for adults are a constant source of debate. While some studies link coffee to raised blood pressure and cholesterol, others even suggest that it could reduce the risk of dying prematurely from heart disease. 

The findings of the research in question here, presented to the American Society for Reproductive Medicine’s (ASRM) congress in Philadelphia by the US National Institutes of Health, were gleaned from a 2014 study that looked at the effects of aspirin during pregnancy. 

Participants included 1,228 women, who were asked to report how much caffeine and alcohol they drank, as well as how much they smoked. Levels of caffeine in their blood were also measured.

The team behind the research said that “any level of caffeine intake during pregnancy may increase risk of pregnancy loss, particularly in the first eight weeks”. They also suggested that women should also consider eliminating caffeine in the lead-up to conception, stating that “women attempting to conceive may benefit from eliminating caffeine intake both during pre-conception and in early pregnancy.”

However, as Hugh Taylor, vice-president of the ASRM, said: “The data on caffeine intake and pregnancy remains somewhat inconclusive. However, it is hard to see any harm that could come to women or babies from reducing or eliminating caffeine.” 

So, it is a case of the better the devil you do than the devil you don't? To minimise any worry in the first 12 weeks when miscarriage risk is slightly higher, perhaps avoiding caffeine altogether is an easy lifestyle choice to make, just in case?

However, as obstetrics and gynaecology doctor Dr Brooke Vandermolen (AKA @theobgynmum) points out, previous recommendations have stated that small amounts of caffeine in pregnancy are unlikely to cause any harm.

“The new research that has come out hasn’t yet been published and therefore hasn’t been through a full peer-review process so it is difficult to determine if it was a reliably designed study,” she says. 

“Looking closer at the study itself, it was actually a secondary analysis which means it was data collected for a different study about aspirin and pregnancy loss that was then interpreted to look at caffeine. 

“Therefore I would suggest that while it sounds like an interesting conclusion, this is a controversial area which requires further robust studies assessing fully the evidence that caffeine increases the likelihood of pregnancy loss before we change the guidelines and recommended advice.”

For Vandermolen, there’s  no reason not to continue to follow current guidelines to limit caffeine intake to up to 200mg per day, or to feel guilty for doing so. 

 “Guidance may change in the future as research and further evidence emerges, but at this time, I would advise any women trying to conceive or in early pregnancy to check the NHS choices website for up to date UK guidance for what they should eat and drink in pregnancy,” she urges.

“It is important to make sure we are cautious and don’t over-interpret new research every time a new paper comes out, because this can make it even more confusing to women.”

However, she does note that in early pregnancy, excessive caffeine consumption (over the recommended 200mg) has been associated with miscarriage. While she feels that expectant mothers can currently rest easy if consuming anything below the recommended 200mg per day, she does suggest keeping tabs on intake beyond that.

“It is important to consider how much you are drinking, and how often. Studies have shown that high levels of caffeine during pregnancy can result in babies being born with a low birth weight, which can lead to complications later on,” she says. “For that reason, it is really important to be aware that different drinks have very different levels of caffeine in."

But if a woman does decide to eliminate caffeine completely, are there any health benefits she may be missing out on? “I can’t say I would actively recommend any additional benefits of caffeine in pregnancy. It is a stimulant, and therefore more likely to disturb your sleep at a time that it is increasingly difficult to get a decent night’s kip,” she says.

In any case, many women tend to become more sensitive to the side effects of caffeine, such as palpitations and insomnia. Some may even “go off” caffeine, which can result in nausea during the early stages of pregnancy. “It’s also a diuretic, so it may make you need to pass urine more frequently than you already do,”  adds Vandermolen.