Since having sexual relations while the woman is Niddah is a very serious infraction of Torah law, safeguards are taken to prevent this from occurring, even inadvertently. In the daytime or nighttime period when a woman expects to menstruate, the couple abstains completely sexual intercourse. The nature of the separation and the way to determine when menstruation is expected will be discussed in this chapter.

1. At the time menstruation is expected the couple must abstain from having sexual intercourse. Other expressions of physical affection and even sexuality are permitted during the day or night when menstruation is expected. (Needless to say, once menstruation has commenced all physical contact is prohibited.)

2. If the woman is expecting her period at night she should not fall asleep with her husband in the same bed as she might menstruate while she is asleep unawares and inadvertently remain in the same bed with her husband--which is now forbidden as she is niddah.

3. This period of abstention is on the full nighttime or full daylight period when menstruation is expected. 5. Even if the exact time of the expected menstruation falls in the middle of the daytime or nighttime period the couple must abstain from sexual intercourse from the beginning of the period.

4. A woman who has a regular menstrual cycle i.e. who menstruates on a predictable day, need only abstain from sexual intercourse for one daytime or nighttime period a month. A woman who does not have a predictable menstrual cycle might have to abstain for two or three daytime or nighttime periods. The details of how menstruation becomes predictable and which days to abstain will be discussed in detail in the next chapter.

5. This period of anticipatory abstinence is figured from the time of the onset of the previous menstruation even though the woman continued to bleed for several days. For example: If a woman usually menstruates in the afternoon, thirty five days after her previous menstruation, she is to expect her next menstruation (and abstain from sexual intercourse) from the morning, 35 days after the onset of her previous menstruation. This is true even though the bleeding from her previous menstruation lasted several days. She is only to abstain in anticipation of the onset of menstruation for one full daylight (or nighttime) period. If she did not menstruate then sexual intercourse is permitted in the evening.

6. If a woman began menstruating around sunrise and does not know if she started before or after sunrise, the couple should abstain only in the daytime of the next expected menstruation, as she was definitely bleeding in the day of the previous period. Similarly, if she began menstruating around sunset and it is not known if it started before or after sunset, the couple should abstain only in the evening of her next expected menstruation.

7. However, if the woman menstruates for a very short time--bleeding from just before sunrise and continuing partly into the day, then ceasing on the same day--the couple must abstain from the night of the next expected menstruation until the time in the day when she usually stops menstruating. After that time full sexual relations may resume provided that she has checked herself and she has not menstruated.

8. Since the practice of abstinence in anticipation of menstruation is rabbinic, and not biblically mandated, if there are uncertainties the tendency is to be lenient, although in uncertain cases the rabbi should be consulted.

9. If a woman did not remember the number of days between the onset of her last several menstruations but she does remember the (hebrew) date of the onset of her last menstruation, the couple must abstain from sexual intercourse on the day (or night) of the thirtieth day from the onset of her last menstruation. Our rabbis have considered 30 days to be the average time between menstruations.

10. A woman who has no fixed period must separate on:
I the thirtieth day from the onset of her last menstruation,
II at the time of the interval between the last two periods,
III and on the day of the Hebrew month that her last period occurred.

(Occasionally two or more of these times might coincide.)

The interval of the last two periods is figured as follows: for instance, if she saw today during the day and thirty two days ago even if it was at night, she next separates in another thirty two days during the day. This is further discussed in the chapter on fixing periods.

11. A woman who is more than three months pregnant is considered not to have a period and no separation is required at the time she would have expected her period. 5. However, for the first three months the couple should keep the abstention in anticipation of menstruation even though she knows she is pregnant.

12. A woman who is nursing within 24 months of the birth does not have to have this anticipatory abstention from sexual intercourse. Even if she had a fixed period before giving birth. Even if she stopped nursing she is still assumed to be free from bleeding for twenty four months. However in our times, where "the nature has changed" and women generally menstruate immediately upon cessation of nursing, the couple should adhere to the laws of anticipatory abstention.

13. An elderly couple, where the woman has ceased menstruating regularly, does not need to abstain in anticipation of menstruation. Even if the woman does menstruate occasionally it is considered a happenstance and does not require the couple to abstain, unless she saw three consecutive months 7.

14. If the husband is going away on an extended trip (for business or pleasure) the halacha suggests that the couple should spend some physically intimate time together before they are separated. This applies even if it is the evening when the woman is expecting to menstruate 8. The rabbinic decree of separating in anticipation of menstruation was never meant to apply to such a situation. (This does not apply if it is the woman who is travelling.) If the couple is travelling together they must keep the anticipatory abstinence laws even if they will be in a place where they cannot be physically intimate.

15. Upon returning from a trip, it is a misvah for the couple to share physically intimate time. However, if he returned on the evening when she was anticipating menstruation, they may express their closeness with words and embraces and other physically intimate behavior, nevertheless the couple should abstain from sexual intercourse. If she was expecting her period while he was away he should ask her if she is niddah before resuming physical relations with her, as it is possible that she did not immerse because he was away.

16. A bride who expects her period her wedding night, may still have relations with her husband, as long as she did not start menstruating. The rabbinic decree was not intended to apply to this situation.

17. A woman (with a regular period) who was supposed to immerse on the night when she expects her period (for example, if she had seen a stain seven days prior), should immerse in the proper time, but refrain from sexual intercourse. Other forms of physical intimacy are permitted, provided they will not cause the husband to "spill his seed." If the woman does not normally have a regular period, full physical relations are permitted, even if it is one of the three times where the woman normally would have abstained. 18. A woman travelling eastward to a different time zone on the day when she expects her period should preferably wait until nightfall in the place where she travelled from before resuming full sexual relations. For example, if she travelled from New York to Israel (a seven hour time difference) and the period of separation is during the day, the couple should abstain from sexual intercourse during the day and an additional seven hours into the night.

19. If at the end of this period of abstinence in anticipation of menstruation the woman has not started bleeding, she must do an internal examination to be absolutely sure that she has not started menstruating. This should be a thorough examination (in all the folds and crevices) done with a white checking cloth. If the cloth is free of any reddish tint she is pure and may resume having full sexual relations with her husband.

20. This checking should be done towards the end of the separation period. It is preferable to also check at the beginning of the period of abstinence as well.

21. A woman who has a fixed period may not resume full sexual relations with her husband until she has checked herself. This applies even if many days have passed since the period of abstinence in anticipation of menstruation.

22. It is preferable that a woman not bathe or go swimming at the time she expects her period. This is because she might menstruate while she is bathing without her realizing. If she did bathe she should check herself afterwards.

23. At the end of this period of abstinence from sexual intercourse the husband may not resume full sexual relations with his wife until he asks her if she has examined herself. However, if she is proficient in these laws and comes to lie with him after the time of expected menstruation he can assume that she examined herself and was not niddah. This applies to a woman who has a fixed period or is the thirtieth day for one without a fixed period.