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Onot perishah during pregnancy

16 September, 2003


First I want to thank you so much for taking the time to read and to answer.
I think I just conceived. It is not clear to me whether I have to keep in the first months the onot perishah. And if yes, how do I proceed? Or does it depend on whether I am bleeding or not?


First of all, b’sha’ah tovah.

According to most opinions, you continue to keep the onot perishah for the first 90 days after you last went to mikveh before conception. Thus, assuming you do not have an established veset (veset kavua), you would keep the same date of the Hebrew month as the beginning of your last period, the onah that comes out at the end of the same interval as there was between your last two periods, and the thirtieth day since your last period.

Practically speaking, once you have missed your first period, you will have no date from which to calculate the interval, the Hebrew date, or the thirtieth day. Therefore, if you do not bleed, then you will keep these onot perishah only once. If you do experience a blood flow, then if you are within the 90 days of conception you would calculate the onot as described above. If the bleeding was within the 90 days but the new onot you calculated come out after the 90 days, then you do not have to observe the onot perishah. If you have bleeding after the 90 days have passed, you observe the date of the Hebrew month and the interval date, but not the thirtieth day.

Rav Moshe Feinstein ruled that, following a positive pregnancy test, a woman conducts herself as if 90 days have already passed. Thus, she calculates onot perishah only if she bleeds during her pregnancy. You may want to consult with your Rabbi as to which position to follow.

Please note that bleeding during pregnancy will make you a niddah. Staining during pregnancy is subject to the usual rules of stains; onot are generally not calculated from stains. You should, of course, consult with your physician about any bleeding during pregnancy.

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