Women who are pregnant or trying to conceive should stay away from coffee all together, according to a new study.
While it's currently considered safe for pregnant women to consume a small amount of caffeine daily without harming their baby, new research published in the journal BMJ Evidence Based Medicine suggests caffeine is associated with negative pregnancy outcomes.
The observational study, conducted by Professor Jack James, of Reykjavik University in Iceland, reviewed 1,261 peer-reviewed articles that linked caffeine and caffeinated beverages to pregnancy outcomes.
Those studies were then narrowed down to 48 original observational studies and meta-analyses published in the last 20 years reporting one or more of six major negative pregnancy outcomes, Namely - miscarriage, stillbirth, low birth weight, preterm birth, childhood acute leukemia, and childhood obesity.
Professor James says there are links between caffeine consumption and negative pregnancy outcomes. Photo: Getty Images/iStockphoto
A total of 42 findings were reported in 37 observational studies. Of those, 32 found that caffeine significantly increased the risk of adverse pregnancy outcomes and 10 found no or inconclusive associations.
"The cumulative scientific evidence supports pregnant women and women contemplating pregnancy being advised to avoid caffeine," said Professor James in a statement, adding that "associations" were found with miscarriage, stillbirth, low birth weight and/or small for gestational age, childhood acute leukemia and childhood overweight and obesity, but not preterm birth.
As a result, he adds, current health recommendations concerning caffeine consumption during pregnancy are in need of "radical revision."
Right now, Food Standards Australia New Zealand (FSANZ), the UK NHS, the Dietary Guidelines for Americans and the European Food Safety Authority (EFSA) set the 'safe level' of caffeine consumption to roughly two cups of moderate-strength coffee per day or 200mg.
However, Professor James did point out that it is an "observational study" and the results could be impacted by other factors - such as the women taking part in the studies not knowing the exact amount of caffeine consumed, maternal cigarette smoking and also pregnancy symptoms, as nausea and vomiting, resulting in some women reducing their caffeine intake.
Other experts, not involved in the review, have also commented on the study and questioned the conclusions.
According to Dr. Christopher Zahn from the American College of Obstetricians and Gynaecologists:
"Our guidance remains that moderate caffeine consumption, less than 200 mg per day, does not appear to be a major contributing factor in miscarriage or preterm birth," Zahn told CNN.
Dr. Daghni Rajasingam from the UK's Royal College of Obstetricians and Gynaecologists agreed in a statement to CNN.
"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," he said.
The Royal Australian and New Zealand College of Obstetricians and Gynaecologists has been contacted for comment.