Many have asked regarding the din of pregnant and feeding women with regard to Tish’a Be’Av. Here is a more detailed response for you all to work with.
There are two different approaches today among the poskim with regard to pregnant women fasting on Tish’a Be’Av.
Pregnant Women:
a) Pregnant women in principle need to fast the full fast as they do on Yom Kippur. (Shulchan Arukh 554/5, Rama 550/1) If one starts to feel really weak, develops a serious headache, dizziness, vomiting, high or low blood pressure, one who runs a temperature and requires anti –biotics, has heart palpitations etc then she can break her fast. One is exempt from fasting only when one ‘suffers’ from the fast. Weakness that leads into sickness is enough cause to stop the fast. (Aruch HaShulchan 554/67) The women herself is relied upon to make the call as to when she enters the level of ‘Mitzta’eret’ – the level of weakness or pain that would define her as ‘suffering’ or ‘sick’ but not in danger. (HaRav Mordechai Eliyahu – see Mikra’ei Kodesh 5/4 footnote 6)
This is the difference between Tish’a Be’Av and Yom Kippur. The Yom Kippur fast is only broken when there is danger to life, on any level. Whereas on Tish’a Be’Av a sick person is already exempt even absent any danger.
b) Our generation is considered a weakened generation and therefore pregnant women should NOT fast on Tish’a Be’Av regardless, even if they are feeling ok. Specifically in hot climates where dehydration is so prevalent. ( HaRav Shlomo Zalman Auerbach Halichot beita 25/3 ; HaRav Yaakov Fischer – Shut Even Yisrael vol. 9, 62/10, Piskei Teshuvot 554/5 )
Most poskim seem to follow approach a). I would therefore suggest that since we in Sydney fast during the winter months, if the pregnant women is completely healthy and feels no severe level of discomfort, she should fast. In case of need one can rely on the lenient opinion without any fear of wrongdoing.
Both Pregnant women and feeding mothers must hydrate as much as possible before the fast.
Feeding Mothers:
Feeding Mothers in principle need to fast the full fast as they do on Yom Kippur. (Shulchan Arukh 554/5, Rama 550/1)
Fasting and feeding a baby naturally impact upon the feeding mother by draining her of fluid. This in and of itself does not define the feeding mother as sick.
However, In the case of a feeding mother, if she feels really weak or her milk runs close to dry, she should drink and if need be , eat as well. ( HaRav Mordechai Eliyahu )
There is a debate among the poskim nowadays as to how detrimental it is for a nursing child to have to switch milk supply from its mother to formula. Some poskim are of the opinion that research has shown that the effect is not that substantial that one would require the mother to break her fast. They therefore encourage the mother to adjust the feeding schedule by missing out 2 alternate breast milk feeds and replace those two feeds with a substitute.
However, there are those poskim who hold that the baby’s mother’s milk is so beneficial, providing the immune system of the child with its strongest capabilities that a nursing mother should break her fast if fasting would be the cause of ceasing to nurse or would necessitate moving to formula during the fast. ( HaRav Neventzal quoting the Chazon Ish – see Mikraei Kodesh Bein Hametzarim pg 219) Many are lenient if the baby in unwell and feeding.
Rabbi David Blackman