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

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Ovulation test on Shabbat

2 February, 2007



I am wondering if it is halachically permissible to do an ovulation test on Shabbat – ie the type of test where you must urinate into a cup and insert the test stick for a few seconds. Two lines appear if you are ovulating, one line if you are not.

Thank you very much for the information.


In an ovulation prediction test, urine comes in contact with an indicator, leading to a color change. Because this color change is desirable (it conveys the test result), and because it lasts at least 24 hours, this test creates a problem of tzove'a (dyeing – an activity forbidden on Shabbat). Therefore, you should not perform this test on Shabbat unless there are mitigating circumstances.

When there are mitigating circumstances, such as trying unsuccessfully to conceive for at least six months, then you may use the test as follows, utilizing the halachic principle of indirect causation (grama): do not urinate directly on the sticks and do not insert the sticks in the urine. Place the stick on the edge of a dish and urinate elsewhere on the dish in such a way that the urine will spread to the stick on its own.

It is strongly recommended that you practice this arrangement before Shabbat so that you do not have to fuss with experimenting on Shabbat.

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