Q. If one hast to undergo an important medical procedure, it is generally recommended to do it during the month of Adar, since those are days of good mazal. Does that include the first day of Rosh Chodesh Adar Rishon? Should one have it postponed until later or the second Adar?
A. In question 472 in regard to postponing a court case to the second Adar we wrote: “The Mishna (Meggilah 6b) teaches that besides the reading of the Meggilah and the gifts for the poor, there is no difference between the first and second Adar. Chasam Sofer (O.H. 167) also implies, that besides the exceptions he cites, both months are equal. Nitey Gavriel (Purim 11: 2) in relation to the increase of Simcha and joy inherent in Adar, quotes Rav Tzadok Hacohen zt”l (Likutey Mamorim 16) and Sfas Emes that maintain that the simcha of Adar begins with the first month.
Not all Poskim agree. Sheilas Yaavetz (2: 88) and Teshuvo Meahavo (2: 301) quoting Rashi (Taanis 29a) mention that it applies only to the Adar close to Nisan.
Horav Shlomo Miller’s Shlit”a opinion is that the court case does not have to be delayed to the second month of Adar.”
On question 990 we added: “Derech Sicha, (Miketz p. 188,) Nitey Gavriel, (Purim – Teshuvos 2) et. al., opine that it begins from the first Adar. Nitey Gavriel (ibid. 464) quoting the Munkatcher Rebbe, adds even from Tu Bishvat.”
Horav Shlomo Miller’s Shlit’a opinion is that a delay would depend on the medical advice received. The Rov maintains that the first day of Rosh Chodesh Adar-First, according to some opinions is also preferred and brings good mazal.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a