When used in moderation, coffee and other caffeinated food and beverages including soda, tea and chocolate are probably not a problem.
Consuming more than 300 to 400 milligrams (or three to four eight ounce cups of coffee) per day can increase your risk of miscarriage, Magriples said.
Moderate amounts of diet soda have not been proven to be harmful, but they should be avoided. They’ll add to your daily caffeine consumption and are empty calories, both for you and your baby.