So what's the overall consensus? "Drinking below 200 milligrams is safe if a pregnant woman is able to tolerate coffee, meaning it's not causing onset nausea or sickness," says Jessica Shepherd ...

"There's definitely confusion," said Robin Hilmantel, senior editor of editorial strategy and growth at BabyCenter, an online resource.

The NHS suggests not to have more than 200mg of caffeine a day — with 75mg in a cup of tea and 100mg in an instant coffee. The NHS states: "The more active and fit you are during pregnancy ...