Fasting During a Healthy Pregnancy
Question
Good evening, my wife is in her seventh month of pregnancy and will be in her 29th week on Yom Kippur. The pregnancy has been normal so far, thank G-d. She fasted on Tisha B'Av without any complaints other than weakness and headaches. I wanted to ask when and how to break the fast if necessary, and whether to drink only small amounts of water or if sweetened drinks or soup are also acceptable. Thank you and may you be inscribed for good.
Answer
Shalom!
She should fast as usual, and try to rest and stay in an air-conditioned place. If the pregnancy is normal, there should not be any problem with fasting at all.
If she feels dizzy even when lying down, or if she sees black, which indicates dehydration, she should drink ’by measurements’.
If contractions begin - she should immediately drink a large amount of fluid.
Source
Shulchan Aruch, Section Orach Chaim, chapter 617