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Nidah 42

    • Question: The Halachah requires that a woman who sees even the smallest amount of blood must count seven clean days. This is the assertion of Rebbi Zeira on Daf 66a, who reports that Jewish women took it upon themselves to keep the laws of a Zavah, even if they did not see blood on three consecutive days. (See RASHI and TOSFOS Megilah 28b).

      The seven clean days may only start on the sixth day after the onset of the bleeding, even if she bled for only one day. What is the source of this five-day period of waiting to begin the count?

    • Answer: The key lies in the Sugya of Poletes Shichvas Zera. The conclusion of the Gemara is that if a woman expels Shichvas Zera, it causes her to cancel her count of seven clean days, had she been counting previously. Shichvas Zera, however, only cancels a clean count if it is expelled within a seventy-two hour period following Tashmish.

      To which woman is the Sugya referring?

      1. RABEINU TAM (quoted in the Rosh 4:1) claims that the Sugya is referring to a woman who expels the Shichvas Zera of a Zav. His proof stems from the statement "Dayah k'Bo'alah" (it is enough to make a Poletes cancel only one day of seven clean days, similar to her partner). Most Rishonim learn that this is referring to a man in general, not her partner in particular. Should he be a Zav, he would only cancel one day if he emitted Shichvas Zera during seven clean days. Rabeinu Tam learns it literally; the only Poletes who cancels seven clean days is one whose partner is a Zav.

        The ROSH has difficulty with Rabeinu Tam's opinion. The verse from which our Sugya proves that an emission of Shichvas Zera cancels a clean count refers to every Poletes - not just one who had relations with a Zav. Furthermore, it is evident from other parts of the Sugya that we are dealing with normal marital relations - not relations with a Zav.

      2. RA'AVAD learns that a Poletes Shichvas Zera only cancels seven clean days with regard to Taharos and not with regard to being permitted to her husband.

        The Rosh (ibid.) has equal difficulty with this opinion. He objects to the possibility that she can cancel her count selectively - for Taharos and not for her husband, and maintain two separate counts. He refutes all of the Ra'avad's proofs.

      3. RABEINU YONAH, cited by the ROSH (ibid.), explains that the Sugya refers to all women who are Poltos Shichvas Zera. As a result, all women must consider the possibility of unwittingly expelling Shichvas Zera, and may not start counting seven clean days until seventy-two hours after Tashmish. This is the conclusion of TOSFOS (33a DH Ro'ah) as well.


  2. The SHULCHAN ARUCH (Yoreh De'ah 196:11) rules that a woman who expels Shichvas Zera and has her period afterwards must wait 72 hours before she can start seven clean days. He brings the example of a woman who had relations on Motza'ei Shabbos, and saw blood afterwards. Even if the blood flow stopped immediately, she starts the seven clean days only on Thursday. She cannot count Wednesday as the first day of her seven clean days, since she may have been Poletes Shichvas Zera on the preceding night before the hour of Tashmish on Motza'ei Shabbos, which cancels that day. Because of this, even if a woman saw blood during the day and not at night, she must wait 4, and not just 3, days until starting her seven clean days.
  3. The REMA (ibid.) writes that the custom adopted by Ashkenazim is to add an extra, fifth, day of waiting, whether she saw blood or found a stain of blood on her clothes. The source for the extra day is the TERUMAS HA'DESHEN (#245), who takes into account the possibility that relations took place Bein ha'Shemashos, and that she saw blood then, also. If she considers Bein ha'Shemashos to be day, she may mistakenly start counting from Wednesday, when she should rather start on Thursday. To avoid such a problem, he instructs that seven clean days only start on Friday when a woman saw blood on Motza'ei Shabbos (see Divrei Chamudos on the Rosh, 4:2)
  4. The SHACH (Shulchan Aruch ibid.:20) explains that the Terumas ha'Deshen rules that a woman must wait to begin her count even if her husband was out of town ("Lo Pelug Rabanan").
  5. Even more so, certain communities adopted the custom that a bride, too, must wait five days before she starts seven clean days. The TAZ (ibid.:7) argues with regard to the bride, claiming that there is no reason for her to wait, since relations never took place. She may start seven clean days as soon as she is Tehorah.


  1. THE CRY OF AN UNBORN BABY HALACHAH: It is clear from the Gemara that as soon as the cry of a newborn baby is heard, it is considered to be the beginning of the baby's birth. Therefore, if we hear the baby cry on a Friday and the baby was actually born on Shabbos, the Bris will not be performed on the next Shabbos.

    The NODA B'YEHUDAH (Yoreh Deah 2:120) was asked if a woman is considered to be Teme'ah if her husband heard the cry of her unborn baby while she was sleeping, and later no indication of birth was found. Do we assume that the baby must have stuck its head out of the birth canal, and whenever the birth canal opens some blood exits, so the woman is a Nidah? Or is it just too unrealistic to assert that the baby stuck its head out of the womb without even waking its sleeping mother, and the woman is Tehorah?

    The Noda b'Yehudah ruled that not only is the woman a Nidah, she is even a Yoledes (and Tamei for two weeks, due to the possibility that her child was female), since it is apparent from our Sugya that a baby's cry can only be heard once the baby is Halachically considered born.

    However, the Noda b'Yehudah agreed to the author of the question that it is highly unlikely that a woman would remain asleep while she is going through such advanced stages of birth. Since the wife remained asleep, she is only Teme'ah mi'Safek, and not for certain.

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