Fasting on Yom Kippur and Pregnancy
Dr. Claude Allouche, Obstetrician-Gynecologist
Ahuza Clinic, Raanana, Israel
Phone: 058 726 02 64 
Every year, before each fast, my pregnant or breastfeeding patients ask me whether they can or should fast. This question is more religious than medical, but since Judaism and medicine are not incompatible, I have studied the halakhot (Jewish laws) as a Jewish gynecologist. Naturally, the answer cannot be simple or definitive, as in our religion there are always discussions among decision-makers.
Here are some guidelines:
First, not all fasts carry the same importance: Yom Kippur and Tisha B’Av seem to be the most significant, while for other fasts, like the 17th of Tammuz, the 10th of Tevet, or the Fast of Esther, pregnant women are more easily exempted.
For the fasts of Yom Kippur and Tisha B’Av, a pregnant or breastfeeding woman, or one who has had a miscarriage:
- MUST FAST
- but only IF SHE FEELS CAPABLE.
Each person must be honest with themselves about whether they can fast or not.
Some believe that modern comforts, such as air conditioning and dietary measures, make fasting easier (avoid salty foods the day before, hydrate well with grape juice, watermelon, melon, or juicy fruits).
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If she feels unwell or unsure how she will cope, she should start the fast, and at the first sign of weakness, she is allowed to eat without asking a Rabbi. This also applies to women who are less than three months pregnant.
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If she has doubts about her health regarding fasting, she should consult her doctor. If he cannot decide, according to the strictest decision-makers, she should begin the fast and eat at the first sign of fatigue or weakness, before the symptoms worsen.
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Some rabbis make distinctions. In case of illness, she must definitely eat and drink.
However, there are various opinions. According to Rabbi N.E. Rabinovitch:
a. Before 20 weeks of pregnancy, a woman should start fasting, but if she feels unwell or vomits, she may drink according to the leshiourim method (explained below).
b. After 20 weeks of pregnancy, she should drink leshiourim from the beginning of the fast.
c. A breastfeeding woman (even partially) drinks leshiourim from the start of the fast to ensure her milk supply is not affected.
d. During labor, if her water breaks or there is bleeding, she can drink without limits.
e. If drinking is insufficient in these cases, she is allowed to eat, but within limits, following the leshiourim method.
- A woman who has given birth is exempt from fasting for the first 7 days postpartum. Some rabbis extend this to 30 days.
For others:
- A breastfeeding woman is exempt from fasting if:
- The baby refuses substitute milk.
- During the fast, she notices a drop in her milk supply. In these cases, she is allowed to eat and drink freely to feed her child.
- The baby is ill (even without danger), and the doctor advises that fasting could weaken the baby or stop milk production, allowing the mother to eat for the baby’s sake, as needed.
If one must eat on Yom Kippur, how should it be done?
According to the leshiourim method:
a. The amount of drink is personal. To measure it, fill the mouth with water before the fast starts; half of that amount is considered leshiourim.
b. If one hasn’t measured, they should use an average measure of 40 cm³.
c. There are differing opinions on the interval between sips: some say 30 seconds, others 9 minutes, depending on the rabbi.
d. Ideally, the longer interval should be followed, but if necessary, one may rely on less stringent opinions.
e. For food, the maximum quantity allowed is 30 cm³, roughly equivalent to 30 grams, every 9 minutes.
f. When there is no longer a need to drink leshiourim, one should stop, as each drink is considered a new act. According to Halacha, fasting is not “broken” by this method, and the obligation to fast persists if one’s health allows.
It is preferable, in cases where drinking is permitted, to consume nourishing drinks like natural juice or milk.
These recommendations apply only to Yom Kippur. For the 9th of Av, if one needs to eat or drink, there are no halakhic issues with doing so normally, without small quantities.
Good to know:
What is considered a pregnant woman?
According to the Gemara, a fetus is only recognized after three months of pregnancy. Thus, a woman would only be considered pregnant from this point on. However, early pregnancy symptoms like nausea and vomiting appear before this and can hinder fasting. Some rabbis, noting that people today are generally weaker, consider pregnancy to be recognized from 40 days, corresponding with the Mishnah from 2,000 years ago that states the fetus is considered alive with a neshama (soul) at this stage. This aligns with modern embryology and the visibility of the fetal heartbeat.
What is considered a breastfeeding woman?
According to the Gemara, a woman is considered breastfeeding within 24 months of giving birth, even if she stopped nursing much earlier. According to Halacha, it takes two years for a woman to recover from childbirth, so during this period, she may decide for herself whether to fast or be exempted from the fasts of the 17th of Tammuz, the 10th of Tevet, or the Fast of Esther, based on how she feels.
In summary, common sense prevails in these guidelines, prioritizing the mother’s and child’s health:
- Do not fast if you have an associated illness that could worsen due to fasting (diabetes, hypertension, weight loss).
- When unsure, consult your doctor.
- If the doctor doesn’t know, begin the fast, but eat at the first sign of weakness.
- Do not fast if you gave birth less than 7 days (or 30 days) ago.
- Do not fast while breastfeeding if it risks stopping milk production or endangering the baby or mother.
Sources:
https://www.torah-box.com/halakha-time/une-femme-enceinte-qui-allaite-doit-elle-jeuner_7018.html
https://www.lejudaisme.org/les-femmes-enceintes-ou-allaitantes-pour-le-jeune-de-ticha-beav/