Short answer: 200 mg. a day, tops, under 150 mg. a day to be extra safe.
Longer answer: After years of conflicting studies on the safety of caffeine during pregnancy, there is real evidence that consuming more than 200 mg. a day is potentially harmful. In 2010 the U.S.’s leading ob/gyns published an opinion that higher amounts in the first 20 weeks of pregnancy were associated with miscarriage and stillbirth. And in 2013 a study of 60,000 women in Norway found an association with caffeine intake above 200 mg. and small-for-gestational age babies. Interestingly, it also found an association between coffee drinkers and longer-than-average pregnancies. Scientists think this is because caffeine makes blood vessels constrict, stunting the baby’s growth. There also appears to be an association between caffeine intake above 150 mg. during pregnancy and obese children.
On the upside, both studies suggest that lower amounts of caffeine are just as safe as none at all.
So how much is 200 mg.? About one 12-ounce cup of home-brewed coffee, half of a Starbucks venti, three cups of black tea tea or six cups of green tea.
|Product||Amount||Mgs. of caffeine|
|Starbucks(r) coffee||20 oz. (venti)||415|
|Dunkin' Donuts Coffee||14 fl. oz. (medium)||170|
|Black Tea||8 oz. brewed 3 min.||30-80|
|Green Tea||8 oz. brewed 3 min.||35-60|
|Coke, Pepsi, Diet Coke||12 oz.||35|
|Mountain Dew||12 oz.||55|
|Hershey's Milk Chocolate Bar||1.6 oz.||9|