Fasting and Breastfeeding

Abstract: The Jewish calender has six fast days which have different levels of stringency. On Yom Kippur and the Ninth of Av it is assumed that healthy women nursing healthy babies will undergo a 24 hour fast (no eating or drinking). Most mothers and babies will not experience negative consequences. However, the physician should convey any specific medical concerns to the woman and her halachic advisor so appropriate arrangements can be made. On the other fasts (which last only from dawn to nightfall), nursing women are not required to fast, although, according to some opinions, they may do so. If the physician feels a woman should not fast on the minor fast days, this should be indicated.

Discussion: The Jewish calendar includes six fast days, which have different levels of stringency.

• The strictest fast, and the only one required by biblical law, is Yom Kippur, the Day of Atonement for sins. On Yom Kippur  both eating and drinking are absolutely prohibited for a little more than 24 hours, from sunset on one day until after nightfall the next day. Bathing, applying oil to the skin, sexual relations and leather footwear are also forbidden.
• Next in stringency is the Ninth of Av (Tisha B'Av), the fast that commemorates the destruction of the First and Second Temples in Jerusalem. This rabbinically-ordained fast is parallel to Yom Kippur in that eating and drinking are prohibited for a little over 24 hours and bathing, etc., is proscribed.
• Three additional "minor"  fasts (the 10th of Tevet, the 17th of Tammuz, and Tzom Gedaliah) mark other events connected with the destruction  of the Temples. The Fast of Esther falls on the day before Purim and commemorates the fighting between the Jews and their enemies. These fasts are less rigorous: eating and drinking are prohibited but only from before dawn until nightfall, and bathing, etc., is permissible.

Healthy breastfeeding mothers of normal, healthy babies are obligated to fast on Yom Kippur and the Ninth of Av. On the other, minor fast days they are exempt. There is debate among halachic authorities as to whether they may voluntarily choose to fast on those days or not.

If there are any health or medical problems with the mother or baby, the mother should not fast on the minor fast days. In cases of actual danger to health, there may be room for leniency even on Yom Kippur and the Ninth of Av. In such cases, an individual question should be asked of a rabbi. The medical information should include the proven importance of breastmilk to health of children [1]. 
 
A woman's fluid output is greater when she is breastfeeding than when she is not. Thus, there is a greater chance that she will develop  symptoms of dehydration, such as headache, fatigue, etc. A woman can reduce her chances of developing such symptoms if she is careful to drink extra fluids before the fast, spends the fast day in a cool environment, and minimizes exertion. Fasting is more important than synagogue attendance. If symptoms are severe, an individual question should be asked of a rabbi, as health concerns take precedence in Jewish law.

There are anecdotal reports by women that fasting causes a decrease in milk production, and mothers are often concerned about the effect of the fast on their babies [2]. This topic has not been adequately studied. A Medline search reveals no studies on the effects of fasting on milk production. One study, indicates that fasting causes a small, temporary decrease in milk production, which is easily reversed [3].

Please see the Case Study, Breastfeeding and Yom Kippur, for additional discussion of this topic.

Implications for Care: Health care providers should be aware of the presence of fast days in the Jewish calender. The epidemiologic evidence suggests that healthy mothers of healthy infants can fast without negative consequences. For these women, the physician should give anticipatory guidance how to best manage the fast (e.g., drink extra fluids the two days in advance, minimize exertion during the fast, and be prepared for the possibility of some temporary difficulty the day after the fast).

When the physician is concerned about the effects of fasting on either the mother or baby, this information should be conveyed in advance of the fast to allow the woman to ask her rabbi whether she may eat. The information should include the importance of breastmilk to the health and development of children.

Medical References

[1] American Academy of Pediatrics. Breastfeeding and the Use of Human Milk. Pediatrics 2005;115:496-506.

[2] Ertem IO, Kaynak G, Kaynak D, Ulokol B, Glunar SB. Attitudes and practices of breastfeeding mothers regarding fasting in Ramadan. Child: Care, Health and Development 2001;27(6):545-54.

[3] Sheffi O. Tzom yom kippur v'hashpa'ato al nashim meinikot. Assia 5754;14:126-141. (Hebrew)

Breastfeeding and Yom Kippur

The question below was submitted to www.yoatzot.org, Nishmat's Women's Health and Halacha (Jewish Law) website for the lay public.

"I am exclusively breastfeeding my son, who is 5 and a half months old. I have heard a full range of opinions on whether or not I must fast on Yom Kippur. From what I understand, the main question is whether I should drink or eat in halachically acceptable small amounts (shiurim) a priori, or if I should wait if/until I feel dehydrated and then drink - risking that I will have to drink more at that point. I feed my son every 3-4 hours and I am his only source of food."

Physicians are commonly asked questions about fasting while breastfeeding. It is important to understand the halachic background to the question, and the dearth of medical information on the topic.

The Shulchan Aruch clearly states that breastfeeding women should fast on Yom Kippur in the same manner as others (Orach Chaim 617:1). As in all areas of halacha, if there is a medical risk, there is room for leniency in individual cases. A rabbi must be consulted in such situations. The physician can assist the woman by providing a clear explanation as to why fasting would create a particular risk in her situation.

Fasting by a breastfeeding woman raises questions as to the health of two people, the mother and the baby. Most breastfeeding women can fast without any risk to themselves. Many report, however, that fasting while breastfeeding is harder than it is at other times. An as of yet unpublished study by the medical supervisor of this site showed that 78.1% of 29 women reported symptoms while fasting; nevertheless, all but 2 completed the fast. Symptoms included headache (n=13), fatigue (n=17), nausea (n=5), dizziness (n=9), and a feeling of reduced milk supply (n=9).

Based on physiologic logic, the physician should suggest that the woman make all efforts to drink additional liquids throughout the day (or even two days) before the fast. She should also be counseled to rest as much as possible during the fast. Women should be told not reduce the frequency of breastfeeding during the fast, as this is likely to lead to painful engorgement, reduction in milk supply and/or mastitis.

As far as the effect on the nursing infant, there is almost no data on the effect of such a fast on human breastmilk. The only published article to date is by O. Shefi: "Tzom Yom Hakippurim v'Hashpa'ato al Nashim Menikot" (published in Hebrew), in Assia 14, Elul 5754. In her review article, the author found one human study that showed a slight difference in milk composition after an overnight fast. Studies in animals showed changes in composition and a small reversible decrease in milk supply the day following a 24-hour fast. The author reported anecdotal data from women she interviewed of reduced milk on the day after the fast. However, no statistical data are provided. In the same unpublished study, 42.4% of the women who completed the questionnaire reported symptoms in the baby. Symptoms included increased crying (n=5), increased sleepiness (n=4), and a need for supplemental feeding (n=6, all but one used expressed breastmilk).

Statistically significant differences were found in calcium, phosphorus, lactose and protein when comparing milk before and immediately after the fast. These differences are not likely to be clinically significant when dealing will healthy full term infants. However, they may have an impact in the case of infants with health concerns. Based on the experience of the medical director of the site, as a pediatrician, lactation consultant, and breastfeeding mother, most babies can weather the fast with little more than slight fussiness. Mothers can help by being prepared with a bottle of expressed breastmilk from the previous day that can be administered at the end of the day (either by bottle, syringe, cup, or spoon, depending on the age and nursing history of the baby). Mothers should arrange to have a quiet day immediately after the fast when they can spend time with the baby and nurse more frequently to make up for any slight decrease in supply that might have resulted from fasting.

These are general guidelines. There are individual cases such as sick infants, difficult nursing situations, and past bad experiences where mothers should be told to drink in shiurim (small quantities). Any such case requires an individual medical assessment of the situation and an individual halachic ruling.