Hilchos Niddah Siman 184, Seifim 2-5

Siman 184, Seifim 2-5:

2. At the time of her vesses, he needs to separate from her for one onah and not have intercourse, though other physical expressions of affection are permitted. If her vesses occurs during the day, he separates from her for the entire day even if it normally occurs at the end of the day. If her vesses does not come during that onah, intercourse is permitted immediately after nightfall. Similarly, if her vesses is normally at the beginning of the day, he separates from her for that entire day and intercourse would be permitted on the previous evening. The law is the same if her vesses is to occur at night – he separates for the entire night and intercourse is permitted during the daytime before and after. This applies whether her vesses has been established one time or three times. All of this applies only if her vesses is contingent on the passing of time, but not if it is contingent on a physical symptom (Bais Yosef quoting Ra’vad). See also Siman 189 below. If a woman’s vesses varies 2 or 3 days earlier or later, he needs to separate from her two or three days before or after (HaGaos Maimonis 8) and see below Siman 189.

3. This law applies for a mature woman, but he does not need to separate at the time of her vesses from a minor who has not reached puberty and has no indications of maturation, unless her cycle has been established 3 times. The law is the same for a menopausal woman.

4. If she normally has her vesses around dawn and she is not certain whether it starts before or after dawn, she is only prohibited during the daytime.

5. If her vesses normally begins before dawn and continues into the day, she is prohibited at night and for the part of the day during which she experiences her vesses.

Onah – What is it and How Long?
There are several important points raised in this Seif, one of which is a definition of an onah. Most of the poskim hold that an onah is the period from sunrise to sunset or from sunset to sunrise. This means that at certain times of the year, a woman with a nighttime onah will have a relatively short onah (such as in the summer) and will at other times have a long one (during the winter). Implicit in this is that a woman's cycle is in some way related to the cycle of the sun; exactly how is not described. However, the Aviasaf, supported by the Shach, maintains that all onos are 12 hours long[1]. It is unclear exactly how we would define the beginning and ending of each onah and the matter is not covered extensively in Halacha, simply because we do not hold of that opinion. The Chochmas Adam maintains that we should use the longer of the two and begin the 12-hour count at the beginning of the regular onah.[2] Another view maintains that the 12 hour period of the Aviasaf is 12 hours prior to the anticipated hour of her vesses, and that in order to maintain simplicity, the decree is on the preceding onah. This of course connects the Aviasaf with the Onas Ohr Zarua described below, for which there is no basis. Yet others understand it as 12 hours forward from the anticipated start of the vesses.

In connection with discussion of the length of an onah, R. Wozner was asked to rule in a case in which a woman got onto an airplane to Israel at the very start of what would be a long onah, and got off the plane, relatively few hours later and found that sunset was falling. The question she asked to R. Wozner was whether she should add whatever part of the night corresponds with the length of what her onah would have been had she been home. R. Wozner answered in the affirmative[3].

This p'sak troubles me for a couple of reasons. First, it breaks the implicit link between sunrise/sunset and the woman's cycle and second, it implies that if a woman were traveling in the other direction and the day at her destination was much longer than that back home, the woman could end her onah prior to the end of the day, because we are apparently following the onah of her place of origin. Finally, if a woman travels north or south within the same time zone, does she make an adjustment for the change in length of day or does she simply follow the sunset at her destination. I have no answers right now to these questions and if I ever do, I will post them here.

Onah - which one?
As I noted in the introduction, there is a significant argument over which onah the Halacha is talking about. The entire matter is based on an argument in the Rishonim in Niddah 16a and I will not review that here. Our Halacha follows the Taz and understands that the onah referred to is the one in which the woman's bleeding is anticipated to begin, and I have defined the term accordingly, above.

There is however, the view of the Ohr Zarua, supported by both the Bach and Shach, that the onah referred to is the one prior to that, functionally imposing a 24 separation rather than a 1 onah separation. There is a growing custom to observe this view and it is without question not required by Halacha and in my view, one should not adopt it; if a couple chooses to, they need to understand that the Onas Ohr Zarua is not Halacha, but is stringency.

Basis for Requirement
The Gemara quotes the verse “Thus shall you separate the children of Yisra’el from their uncleanness”[4] and derives from this that a man must separate from his wife near the time of her expected menstruation. This means that the prohibition of intercourse with a woman does commence at the start of menstruation but at some earlier time, in anticipation of its commencement. Although this law is derived from the verse, there is a lengthy discussion among the poskim about whether this is really a Torah law or a Rabbinic one. The general consensus is that it is Rabbinic[5] and is certainly so in the case of a Vesses SheAino Kavua. Some understand the Torah based prohibition as being from the anticipated time of the vesses until the end of the onah. This dispute does have some impact on practical Halacha as discussed in Seif 9.[6]

Extent of Prohibition
During the onah separation, only intercourse is prohibited. Although other forms of affection are permitted, one should refrain from them.[7] There is also a view that prohibits all forms of affection[8], though we do not hold by it for halacha.

Miscellaneous
The Rama’s comment at the end of Seif 2 is rather cryptic. The way it is understood by the poskim does not introduce any new law that is not covered elsewhere and with greater clarity.

Seifim 4 and 5 seem strange given that women’s menstruation typically lasts for several days , while these laws imply that a woman’s flow is actually of a very short duration. In order to make sense of this, we need to accept the fact that in the past, menstrual habits, as well as other physiological aspects have changed. These changes might result from total population, diet, people’s relationship to their environment and general living conditions. An example of this is that over the past 200 years the average age of onset of menarche for a girl has decreased from 17 years to about 12.6 years. It is not difficult then to imagine that other changes have taken place over the 1500 years since the Talmudic era.

Back to Summary
Back one page
Forward one page
Have a question?