There is halachic debate as to whether relations are permitted on the 9th of Av when it falls on Shabbat and the fast is delayed until Sunday. In your situation, relations would be permissible. On Saturday night and Sunday, when the fast of Tisha B’Av is actually observed, relations are prohibited.

Please feel free to get back to us with any further questions. As you navigate treatment, you may also find it helpful to arrange a free consultation with a Yoetzet Halacha Fertility Counselor, details here.

B’Hatzlacha!

This response was updated on 23 May, 2021.