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

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Irregular veset on pill

4 May, 2016


I have a question about vestot on birth control pills.
We hold that I must keep all of the vestot until 3 cycles on the pill, and then I can go based on the interval from the last active pill. For some reason, I am having a hard time figuring that interval out.
I used to take the pills in the morning, but now I have a hard time remembering to do so, so I take my birth control pills in the evening or before bed. Unfortunately, this time varies quite a bit, and now I am confused as to how to count the interval: by hours, by onot, by days. Below is the relevant information I wrote down on my chart. I take six weeks of active pills, and always take my last pill on a motsai Shabbat. I know I have an extended veset, but I am having a hard time calculating it. So far I've been counting from Saturday night, sort of using onot. Any advice is appreciated:

  • Last pill Saturday evening, period Wednesday Day; 4 days (kept all vestot)
  • Last pill Saturday evening, period Wednesday Day; 4 days (kept all vestot)
  • Last pill 2am Sunday; period Thursday Night; 5 days? (kept all vestot)
  • Last pill Saturday almost midnight); period Friday Day; 5.5? 6 days?
  • My last pill was three days ago, 3am Sunday.

Thank you so much:


In calculating vesatot, you should ignore hours.  As long as you continue taking your last pill Saturday night between sunset and sunrise, just look each cycle at the earliest daytime/nighttime on which you became niddah over the most recent three cycles.

Your veset observance this month starts on daytime Wednesday (today), since that is the earliest onah (daytime or nighttime) in which you have become niddah over the past three cycles.  If you become niddah this cycle only after Wednesday daytime, you will be observing next cycle starting from a later point.

Please write back with any further questions.

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