Surgery and childbirth can trigger attacks of hereditary brachial plexus neuropathy (HBPN), and inflammation was suggested as a component of the pathogenesis. HBPN patients who underwent surgery or parturition from January 1, 1996 to December 31, 2009 were studied. Twenty-five HBPN patients underwent 48 surgeries or parturitions. Seventeen patients (68%) had attacks, including 13 periprocedural and 7 postpartum by varied anesthesia types. Three patients who had 8 earlier combined attacks (after thyroidectomy, laminectomy, and Caesarean section) were given prophylactic immunosuppressive therapy (corticosteroids ± immunoglobulin). None suffered postoperative attacks, which is uncharacteristic of their prior experience. Five had perioperative attacks as their first HBPN manifestation. Median follow-up was 11 months (3-48 months). Attacks occurred in the operated limb (n = 6) or distant (n = 7) to surgical sites. All attacks interfered with daily living, with frequent incomplete recovery. Five patients had a SEPT9 mutation. Corticosteroids may prevent parturition and surgical HBPN attacks in some patients. Diverse surgeries, anesthesia, and childbirth frequently trigger HBPN attacks.