BeSha’ah tovah!

Tisha B’Av is a rabbinically mandated fast. Though more serious than the other rabbinic fast days (Tzom Gedalyah, Asarah BeTevet, Shivah Asar b’Tammuz, and Ta’anit Esther), there is no issur karet ;involved and in cases of sickness a person may be advised not to fast. Typically, pregnant women should fast on Tisha B’Av unless they become sick or there is specific risk to them or the fetus.

This year, however, since Tisha B’Av is pushed off from Shabbat to Sunday, you should start off fasting, but feel free to break your fast if you start to feel at all uncomfortable or dehydrated. This is halachically fully permissible. Just don’t forget to make havdalah before eating or drinking.

Please consult your physician to confirm that this course of action is safe for you, and write back with any further questions.