During the war, she recruited Doctor Selar of the USS Enterprise-D to serve as both a medic, and to provide a logical, objective viewpoint of the conflict. To end the war, Q agreed to conceive a child with Q. Q gave birth shortly after the conception, with Selar serving as midwife. (VOY episode: "The Q and the Grey"; NF short story: "'Q'uandary")
She later appeared on the USS Enterprise-E in 2374, when Betazoid scientist Lem Faal's experiments at the Galactic barrier threatened to release the entity known as 0 from his confinement. (TNG - The Q Continuum novels: Q-Space, Q-Zone, Q-Strike)
In 2380, Lady Q appeared to Admiral Kathryn Janeway to warn her away from personally investigating a seemingly dead massive Borg cube. Janeway ignored her warning and Lady Q stood witness as Janeway was assimilated and transformed into the new Borg Queen.
With the destruction of the cube and the apparent death of Janeway, Lady Q took Janeway away from the scene to face some unknown "destiny". She served as a direct participant in the events of the mission by serving aboard the USS Enterprise-E, in the guise of Jon Stephens (TNG novel: Before Dishonor)
It was later revealed that Lady Q had actually come to Janeway on behalf of her son rather than her husband, giving her son a chance to spend more time with his godmother by extending the usual moment typically experienced by mortal beings between life and death so that Janeway existed in this state for over a year. Despite his father's warnings against bringing the dead back to life, Q's son was able to find a loophole that allowed Janeway to 'rebuild' her own body with the aid of Kes when he believed that Janeway was needed to defeat the threat of the Omega Continuum, which she had originally dealt with during the longer journey home that had been cut short by Admiral Janeway's intervention. This crisis resulted in Junior's death when he sacrificed himself to contain the Omega Continuum and reset the balance of the universe without erasing the rest of the Q Continuum- which had been created as a creative force to counter the destruction of Omega- although Q coldly declared himself Janeway's enemy for her role in his son's decision to sacrifice himself. (VOY novel: The Eternal Tide)
Despite this declaration, Counselor Hugh Cambridge concluded that Q must have calmed down and recognised that Janeway had no real blame in his son's decision, based on the fact that they were all still there after several months with no sign of Q's revenge. Q and Lady Q later appeared in an alternate past, caring for the daughter of an alternate version of Kathryn Janeway created by the manipulations of the Krenim, this Janeway kept alive along with her 'primary' counterpart thanks to Q's actions. Musing to his wife that this was his way of respecting his son's memory and acknowledging all that Janeway had done by giving at least one of her a happy ending with a child, Q severed this timeline from the rest of the multiverse for the duration of the other Janeway's lifespan, allowing the alternate Janeway and her child to live in peace. (VOY novel: A Pocket Full of Lies)