House of the Dragon's third season has departed from its source material, George R. R. Martin's Fire & Blood, by having Helaena become pregnant with her third child much earlier than in the book, where her son Maelor is already born by this point in the story. The change, revealed in the episode "Tumbleton" and developed further in "Unbowed and Unbent," gives Helaena and her mother Alicent a more substantial storyline during their confinement in King's Landing, adding fresh tension as the pregnancy could complicate Rhaenyra's claim to the throne.

The pregnancy forces Alicent and Helaena into opposing positions: Alicent secretly obtains moon tea from Maester Orwyle to end the pregnancy and protect her daughter, even taking the blame for infidelity when Mysaria discovers the plot, while Helaena insists on continuing the pregnancy and refuses to abandon her surviving daughter, Jaehaera, to flee the city. The article argues this invented plotline strengthens the show by deepening the mother-daughter dynamic between Alicent and Helaena, which had previously been overshadowed by Alicent's focus on her sons.