Harald died at about 10 from meningitis and his eldest brother, Christian, drowned at 18 when a storm suddenly overtook the boat he was sailing with his father.

In the course of editing (by both of them), transcribing, re-editing, and retyping the many drafts of her husband’s papers, she insisted that he explain his ideas in language that was understandable to his readers.

[1][5] According to Crease, "She was not only Bohr's constant companion, she was also his intellectual collaborator, a sounding board who helped him with his letters and essays, and to explain his ideas to himself.... she was very smart.

She spent a good deal of time with Niels’ various assistants and teammates at the Institute for Theoretical Physics, and later in life recalled not just their scientific successes but the warmth of the home when these young scientists joined them.

[1]During World War II, Margrethe grew concerned when German physicist Werner Heisenberg came to Copenhagen in 1941, apparently to urge her Jewish husband to join him in his research for Germany but Niels was not convinced.

Margrethe and Niels are the primary characters in a play by Michael Frayn, called Copenhagen that dramatizes her role in Bohr's life.

[1][7] The play looks at the couple's real-life collaboration.As Heisenberg and Bohr recall their science, they remind themselves to always be sure that Margrethe can understand the work discussed in plain language.