Pregnancy and fasting on Tisha b’Av
Rabbanit Rachel Weinstein
She'elaB"h on tisha b'av this year I will be 34.4 weeks pregnant with my first. What are the halachot pertaining to late pregnancy and fasting? Thanks!
The general rule is that we are much more lenient regarding the "small" fasts but pregnant women are obligated to fast on Yom Kippur and Tisha b'Av (Shulchan Aruch Orach Chaim 554:5, 617:1). The Rama adds that although pregnant women are not obligated to complete the small fasts, the custom is to be machmir and fast. The Mishna Brura adds that if a pregnant woman experiences even slight weakness on the small fasts that they should not complete the fast. (Mishna Brura 550:3).
As to the difference between Tisha b’Av and Yom Kippur regarding the obligation to fast - We are more stringent regarding Yom Kippur being that it is מדאורייתא and we are more lenient regarding Tisha b'Av.
All of the above is in the case of a pregnancy without high risk or complications.
This year the laws of Tisha b'Av differ slightly since Tisha b'Av is נדחה, postponed. When Tisha b'Av is postponed we are more lenient in regard to the fast. Rav Ovadya in Yechave Daat (3:40, Yabia Omer Orach Chayim 5:40) states that when Tisha b'Av is נדחה , pregnant women who follow the psak pf the Shulchan Aruch don't need to fast at all, while the Shvut Yaakov (3:37) and Rav Shlomo Zalman (Halichot Shlomo 16:1) say that pregnant women should try to fast but may break their fast even if they feel slightly unwell "מיחוש קצת".
Practically this means that if you are healthy and strong and have no additional medical issue that would make fasting a problem, it seems that you should try to fast. If during the fast you feel unwell or have contractions you should break your fast.
I would like to stress that you should not take any chances and if you feel unwell please listen to your body and break your fast if you feel that you need to. I would say this any year but even more so this year since as I've mentioned the fast is נדחה.
I hope the rest of the pregnancy goes well, I would like to wish you an easy and meaningful birth and fast.
Bezr"h we will see full geula soon and the fasts will turn to Moed V’Simcha.