- Besides for the actual mila and p’riah, other procedures such as m’tzitza and medicinal bandaging must be performed on Shabbos. (ShA 1)
- Without m’tzitza, the baby will be in sakanna. M’tzitza b’peh is preferred. Some poskim allow m’tzitza with a sponge. (BeH “ufor’in”)
- A mila that has been postponed (until after the eighth day) may not be performed on Shabbos. (ShA 4)
- A baby born during twilight of Erev Shabbos or Motzoay Shabbos should not have a bris on the following Shabbos. There will be a doubt if Shabbos is the eighth day. (ShA 5 – MB 14)
- “Twilight” is defined as the time between the disappearance of the sun until tzais hakochavim. (MB 14)
- A baby born from a Cesarean section does not have a mila on Shabbos.
(ShA 5)
- Melachos that are necessary in preparation of the mila are not allowed on Shabbos since they could have been done before Shabbos. For example : if the knife was left across the street, you aren’t allowed to carry the knife even by an issur d’rabbonon. You must postpone the mila until Sunday. (ShA 6)
- Another example is the mohel has cracked thumbnails and forgot to sharpen them before Shabbos. He may not sharpen them on Shabbos in preparation for the mila. (BeH “afeelu”)
- Shvus d’shvus bimakom mitzva is mutar. Therefore you can instruct a non-Jew to carry the knife through a karmelis to where the mila will be held. Some poskim even allow a single shvus bimakom mitzva. You can rely upon them for the mitzva of Mila if you have no choice. (ShA 6 – MB 20, 22)
- You aren’t allowed to make a situation of sakanna on Shabbos and then break Shabbos for pikuach nefesh. For example: If you did not grind medicine for the baby’s mila before Shabbos, postpone the Bris until Sunday. Do not perform the mila and then consider the baby in danger in order to grind the medicine. (MB 24)
- You are allowed to give the baby a warm bath before the Mila – with water that was heated before Shabbos. Just be sure not to put the washcloth into the water – it's laundering. (Rama 9 – MB 32, 33)
- You should not attempt your first mila on Shabbos. You might bungle it and it will be chillul Shabbos without fulfilling the mitzva. (ShA 10 – MB 36)
- If a person claims that he has performed a mila once before, you can believe him. He can now be the mohel on Shabbos. (ShA 10 – MB 36)
- The mila, priah, and m’tzitza can be done by three different people whether during the week or on Shabbos. (MB 36)