Laws Of Tish'ah B'av
6. Pregnant and nursing women must complete this fast, even though they are
very uncomfortable, unless, Heaven forbid, there is a possibility of danger
[to life] (1). A sick person, even if he is not dangerously ill, may be
lenient and only fast for a few hours, without having to complete the fast.
This certainly applies if his constitution is weak (2).
[There is no question that a woman who gave birth within a week of Tish'ah
B'av should not fast.] If she gave birth between seven and thirty days
before Tish'ah B'av, she has the status of a sick person who is not
dangerously ill [and is not required to fast], even though she does not
feel sick. Nevertheless, if she feels completely healthy and feels that
the fast will not harm her, she can complete the fast (3).
Those who must eat on Tish'ah B'av should not overindulge in food. Rather,
they should eat only what is necessary for the health of the body.
(1) On the other rabbinically created fast days, some authorities rule that
pregnant or nursing women do not have to fast, while other authorities rule
that the custom is that they should fast, unless they find it difficult.
(2) The Sages excluded sick people from the obligation to fast.
(3) See Rama 554:6.
The basic principle applied in today's halacha is that if a person can be
defined as sick or weak enough to be vunerable to becoming sick, then
he\she is not obligated to fast on Tish'ah B'av. We have discussed three
types of people in this halacha; I will list them here in ascending level
a) PREGNANT AND NURSING WOMEN: These women are not by definition considered
"sick". On other rabbinically created fast days, which are not as stringent
as Tish'ah B'av, these women are not required to fast, because they are
generally weak and more vunerable. However, on Tish'ah B'av, they are
required to fast unless they are so weak that they are likely to become ill.
b) WOMAN WHO HAS GIVEN BIRTH MORE THAN 7 AND LESS THAN 30 DAYS BEFORE
TISH'AH B'AV: These women are considered weak enough to be placed in the
category of "sick" people, even though they are not actually ill.
Therefore, they are exempt from fasting (there are those who disagree).
c) SICK PERSON WHO IS NOT DANGEROUSLY ILL. This person is not obligated to
fast under any circumstances.
It should be noted that because Yom Kippur is a Biblical fast day, even a
sick person is obligated to fast, unless there is a danger to life. If a
person has a question as to whether his condition might exempt him from
fasting, a Rabbi should be consulted.