As we have stated, pregnant and nursing women are obligated to fast on Yom Kippur (Pesa\u1e25im<\/em> 54b; SA 617:1). True, some contemporary poskim<\/em> maintain that nursing women may drink le-shi\u2019urim<\/em>, so that the fast does not cause them to stop nursing. Nevertheless, according to most poskim<\/em>, nursing mothers must fast on Yom Kippur and even Tisha Be-Av. Even though nursing makes the fast more difficult because of the additional loss of fluids, this is not life-threatening. It does not endanger the baby either, because even if the mother\u2019s milk decreases or dries up, milk substitutes are available. In reality, women who fast are generally able to continue nursing.<\/p>\n
Good advice for nursing mothers is to skip every other feeding. This will help them make it through the fast relatively easily. In other words, a woman who normally nurses every three hours should nurse at 10 AM. At 1 PM she should use formula or another substitute, and then nurse again at 4 PM. At 7 PM she should once again use a substitute. This way, she will not suffer too much during the fast, and she will not produce less milk. Some babies will not accept a substitute from their mother, in which case someone else needs to feed them formula.<\/p>\n
Nevertheless, if the baby is small, weak, and sickly, and the doctor thinks that the baby has a special need for mother\u2019s milk, and there is concern that if the mother fasts, her milk will dry up or be considerably depleted, she may drink le-shi\u2019urim<\/em> based on the instruction of a God-fearing doctor (BHL 617:1). However, this is rare; if a nursing mother drinks a lot the day before the fast, her milk will almost certainly not be depleted from fasting. It is even better if, starting three days before the fast, she drinks and sleeps more than usual. This will increase her milk supply. She can also pump in the days before the fast, so the baby will have plenty of milk during the fast, and there is no concern that the mother\u2019s milk will be depleted.[13]<\/a><\/sup><\/p>\n