A U.S. consumer advocacy group says pregnant women should be urged to avoid all caffeine during pregnancy, and that current guidelines that state that moderate amounts of caffeine are safe are outdated.

The Center for Science in the Public Interest says advising pregnant women that it’s safe to drink one to two cups of coffee a day may put them at risk of miscarriage or early delivery, and might even increase their children’s risk of childhood leukemia.

CSPI is a non-profit group that made its mark warning of the high calorie content of movie theatre popcorn and shaming restaurant chains for high-fat menu items. It’s also long warned about the risks of caffeinated energy drinks and campaigned against the addition of caffeine in food.

Now it says it’s worried about the draft advice from the U.S. government’s Dietary Guidelines Advisory Committee, which urges pregnant women to limit their caffeine consumption to 200 milligrams per day.

That’s even lower than the guidelines given by Health Canada, which advises pregnant or breastfeeding women to limit their caffeine intake to 300 mg of caffeine per day, or about two 237-ml cups of coffee.

The CSPI says it worries the U.S. guidelines are too high and give women the impression that caffeine intake below that threshold is safe.

In comments the group filed to the U.S. Dietary Guidelines Advisory Committee, CSPI says pregnant women should instead be advised to avoid caffeine-containing foods and drinks altogether.

They point to a recent study published in the European Journal of Epidemiology.

That meta-analysis found consuming as little as 100 mg of caffeine a day was linked with a 14 per cent increase in risk of miscarriage, and a 19 per cent increase in the risk of stillbirth. It was also linked to low birth weight.

The authors of the study cautioned that many of the studies they reviewed were weak and lacked reliable consumption data, and said that further research was still needed to draw firm conclusions.

CSPI also points to a 2014 meta-analysis published in the American Journal of Obstetrics and Gynecology that noted a link between childhood acute leukemia and maternal coffee consumption. That study also noted a shortage of good studies on the link and said more research was needed.

The CSPI says that until more research has been done, the U.S. Dietary Guidelines Advisory Committee should return to using the stronger language the U.S. FDA used decades ago when it urged all women to avoid caffeine while pregnant.

“Pregnant women deserve accurate advice about the risks caffeine poses to their healthy pregnancy and have been badly misinformed,” CSPI chief regulatory affairs attorney Laura MacCleery said in a statement.