[1] She was born in Drøbak as a daughter of ship captain Nils Høgh Isachsen (1838–1913) and Cecilie Marie Sivertsen (1839–1909).
[1] She was a medical candidate at Rikshospitalet and Kristiania Municipal Hospital from 1901 to 1902 (together with fellow pioneer Kristine Munch), became interested in women's diseases and studied gynecology in Edinburgh in 1902.
From 1908 to 1911 Isachsen was an assistant of Norway's first gynecologist Emil Rode, and studied gynecology abroad again in 1909, this time in Giessen and Berlin.
From 1910 to 1927 she was an assistant of birth doctor Christian Kielland in Kristiania, running the clinic during his numerous stays abroad.
She was active in the contemporary debate regarding abortus provocatus, and held numerous public speeches, lectures and courses on hygiene and related subjects.