Revision Urged to Guidelines on Caffeine in Pregnancy

By Anne Harding

August 26, 2020

NEW YORK (Reuters Health) - Doctors should advise pregnant women and women planning to become pregnant to abstain completely from caffeine, according to a new narrative review in BMJ Evidence Based Medicine.

"For the wellbeing of mothers and babies, health authorities are well-overdue to take a more realistic and responsible position in relation to maternal caffeine consumption," the report's author, Professor Jack E. James of Reykjavik University in Iceland, told Reuters Health in an email. "In short, caffeine should be avoided altogether during pregnancy."

The American College of Obstetricians and Gynecologists (ACOG) and several other health authorities state that moderate consumption of caffeine in pregnancy is not harmful, with some, including ACOG, defining this amount as less than 200mg daily.

In the UK, "Based on current scientific opinion, the Food Standards Agency (FSA) advises pregnant and breast-feeding women not to have more than 200mg of caffeine over the course of a day, which is roughly two mugs of instant coffee or one mug of filter coffee," the FSA told Reuters Health in an email.

The U.S. Department of Agriculture (USDA) defers to physicians in its 2015-2020 Dietary Guidelines for Americans, stating: "Women who are capable of becoming pregnant or who are trying to, or who are pregnant, and those who are breastfeeding should consult their health care providers for advice concerning caffeine consumption."

Eighty-two percent of pregnant women in the U.S., and 91% in France, report consuming caffeine daily, Dr. James notes in his report. Caffeine easily crosses the placenta, he added, and is known to affect neural processes, including brain networks that control respiration and heart function.

He analyzed 48 observational studies and meta-analyses of maternal caffeine consumption reporting at least one of six negative outcomes: miscarriage; stillbirth, low birthweight/small for gestational age; preterm birth; childhood acute leukemia and childhood overweight and obesity.

Thirty-seven observational studies reported 42 separate findings, including 32 showing increased risk of harm due to caffeine in all outcomes except preterm birth, while 10 didn't find an association or were inconclusive. Out of 17 meta-analyses, 14 found associations between caffeine and miscarriage, stillbirth, low birth weight and/or small for gestational age and childhood acute leukemia.

"Certainly, there is no evidence to suggest that caffeine benefits either mother or baby. Therefore, even if the evidence were merely suggestive, and in reality it is much stronger than that, the case for recommending caffeine be avoided during pregnancy is thoroughly compelling," Dr. James said.

"It is important for the public to understand that caffeine is not the benign substance it is often portrayed to be. Unfortunately, the position of many health authorities to date has been disappointing in this regard," he added. "The idea that there is a safe level of maternal caffeine consumption is a myth that is strongly at odds with the scientific evidence. This accepting attitude towards caffeine and pregnancy must change."

In an emailed statement, ACOG told Reuters Health that it does not plan to change its guidelines at present.

"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," Dr. Christopher Zahn, MD, ACOG's vice president of Practice Activities, said.

"ACOG's clinical guidance is based on a thorough expert review of the most current evidence and is routinely reviewed every 18-24 months. ACOG Committee Opinion, 'Moderate Caffeine Consumption During Pregnancy' was reaffirmed this year," he added. "While this study will likely be included in the next review, there is nothing that warrants immediate change to the current guidance."

SOURCE: BMJ Evidence Based Medicine, online August 24, 2020.