I am currently pregnant and had some issues in the early stages. I asked my doctor about if I may fast and he said I can try; however, there is a chance I might feel cramping in which case I would have to drink large quantities of water. On the other hand I can just drink in shiurim the whole yom kippur and not worry about anything. Which is better: drinking in shiurim or fasting until I definitely know I should break my fast.
Answer:
Our approach (this is not the approach of all rabbis) is that if there is no medical danger to the pregnancy, you should fast as usual.
Of course, if a medical emergency arises that required drinking, you can and must drink, but while there is no such emergency, and the doctor maintains that fasting does not present a direct risk, you should fast as usual.
Best wishes and gemar chasimah tovah.
