Nishmat's Women’s Health and HalachaIn memory of Chaya Mirel bat R' Avraham

  • Hebrew
  • English
  • Espnaol
  • Francais
  • donate

Dehydration on Yom Kippur

10 September, 2009


I am 7 weeks pregnant, with my 3rd child. With my 1st, I was about 11 weeks at 9 Av, and got dehydrated, nearly passing out the following day. With my 2nd, I got dehydrated at 16 weeks – on just a regular day. That episode required 6 hours in the ER and 3L of IV fluids. With both previous pregnancies I had terrible morning sickness; so far this pregnancy I have found that if I eat in the morning the sickness is much less, in fact, sometimes avoidable altogether.

I will be alone with my 3 & almost 2 year old on Yom Kippur; my husband will be in shul. I may go to a friend so that I have some backup, but she also has 4 young children (5 and under).

Is there a circumstance under which I would be permitted to drink in shiurim? If so, how do I know what those criteria are? How will I know if I've fulfilled them, or if it's just "wishful thinking"?


B'Sha'ah Tovah!

The laws concerning Yom Kippur are strict and pregnant women are required to fast on Yom Kippur.  Permission to eat is given in situations in which the fast is a threat to the woman's or fetus' health.

Even in the situation you describe, you should attempt to fast on Yom Kippur, being sure to hydrate yourself well during the two to three days beforehand and to get ample rest (lying down in a cool environment, arranging for help with the kids, etc).  Your fast on Yom Kippur takes halachic precedence over your husband's davening in shul. He has a responsibility to help you get through the fast. Perhaps he can daven at an earlier minyan if you have one in your community, and come home for the rest of the morning to give you a break. You should also look into the possibility of hiring a babysitter. You should make it a priority to arrange such help in advance.

In general, if it gets to the point that you are feeling very nauseated or very weak or light headed despite lying down, you should begin to drink in shiurim. The correct procedure is as follows:

You should drink less than one cheekful (maleh logmav) at a time. The average cheekful is 40 ml, but you should measure your own mouth. Before Yom Kippur, fill up your mouth completely with water, then spit it into a cup and measure the quantity. Half of that is your maleh logmav.

Ideally, you should wait nine minutes between drinks. If necessary, this can be reduced to five minutes or less. If you are sure you will have to drink, it is better to start earlier with shiurim, rather than waiting to become dehydrated and having to drink more than a shiur.

A more personalized ruling depends in part on your specific medical considerations.  Therefore, you should consult with your physician prior to Yom Kippur for his or her opinions on the protocol above and the medical reasoning behind those opinions.  (If you have access to a religious physician, that would be preferred.)  Then you should get back to us or a local rabbinic authority with that information. 


This internet service does not preclude, override or replace the psak of any rabbinical authority. It is the responsibility of the questioner to inform us of any previous consultation or ruling. As even slight variation in circumstances may have Halachic consequences, views expressed concerning one case may not be applied to other, seemingly similar cases. All health and health-related information contained within Nishmat's Women's Health & Halacha Web site is intended to be general in nature and should not be used as a substitute for consulting with your health care professional. The advice is intended to offer a basis for individuals to discuss their medical condition with their health care provider but not individual advice. Although every effort is made to ensure that the material within Nishmat's Women's Health & Halacha Web site is accurate and timely, it is provided for the convenience of the Web site user but should not be considered official. Advice for actual medical practice should be obtained from a licensed health care professional.

For further questions or comments: 

The Nishmat Women's Health and Halacha Site is a public service of Nishmat, The Jeanie Schottenstein Center for Advanced Torah Study for Women. This project and others like it are made possible by contributions from people like you. If you have benefited from the service, and wish to enable us to help others, click here to donate.

Users of Internet filtering services: This site discusses sensitive subjects that some services filter without visual indication. A page that appears 100% complete might actually be missing critical Jewish-law or medical information. To ensure that you view the pages accurately, ask the filtering service to whitelist all pages under

Accessibility Toolbar