On the day of a Bris, during Shacharis, Lam’natza’ach (Psalm 20) is recited between Ashrei and U’va L’sion as on every other weekday. In this psalm it states “May Hashem answer you on the day of distress.” The Maharil states we recite this psalm despite saying “day of distress” because the baby may experience some pain. The Midrash states there are 9 verses in this psalm which correspond to the nine months of pregnancy. But, Sephardim and Lubavitch, do not recite this psalm because whenever Tachanun is omitted, this psalm is also omitted.