Nishmat's Women’s Health and HalachaIn memory of Chaya Mirel bat R' Avraham

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Onset of menses

24 December, 2006


I was expecting to get my period today. Earlier I thought I felt a flow sensation but found no blood on a tampon. I only got to check again at 4:53 pm and then found blood. Can I count today (Sunday 3 Tevet) as my first day of 5?


The halachic day begins and ends at sunset.  Please check when shekiah (halachic sunset) was today – you can use the link for Time of Sunrise/Sunset on this site.  The halachic day on which you became a niddah depends on whether 4:53 was before or after sunset.  If it was before sunset, today counts as your first day and you can make a hefsek taharah as early as Thursday.  If it was after, tonight/tomorrow counts as the first day of your five days and you can make a hefsek taharah as early as Friday.

Uncertainty as to the exact moment bleeding commenced does not affect this halacha.  What matters is the halachic day on which you began to consider yourself niddah.

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