Unfortunately, no solid answer has been decided on this topic. Here are the main points on kombucha and pregnancy:
Yugen Kombucha contains trace amounts of alcohol (0,3%). Most of the alcohol in kombucha is metabolized into acids, but some remnants are left in the finished product.
The caffeine from the original tea steeping is not lost in the culturing process. Although the amount of caffeine in kombucha is fairly small, it is worth mentioning.
Intense detoxification is not recommended for pregnant women. As kombucha aids in many of the bodies detox functions, it is also a point worth considering.