"We were capable of having children, but Astoria was frail. A blood malediction, a serious one. An ancestor was cursed... it showed up in her. You know how these things can resurface after generations... I didn’t want to risk her health, I said it didn’t matter whether the Malfoy line died with me – whatever my father said. But Astoria – she didn’t want a baby for the Malfoy name, for pure blood or glory, but for us. Our child, Scorpius was born... it was the best day of both our lives..."
-- Draco Malfoy (CC2.15)
Astoria is the younger sister of Daphne Greengrass. She entered Hogwarts two years after her sister and eventually married Draco Malfoy. Their only child was named Scorpius Hyperion Malfoy.
Lucius and Narcissa objected to Draco’s choice of a wife, but he defied them. Astoria once told her son that this was one of the most courageous things she’d ever seen. Astoria inherited a family curse from generations before which manifested itself as a fatal blood malediction. She knew that she was not destined for old age and wanted desperately to produce a child so that Draco wouldn’t be alone. Her pregnancy greatly weakened her and the family went into seclusion when Scorpius was born. This led to false rumors that Draco and Astoria had actually been unable to conceive and that Astoria had used a Time-Turner to go back in time and conceive a child with Lord Voldemort. Scorpius bore the stigma of those rumors and was accused of being Voldemort’s child in school.
Astoria passed away at the end of August 2019, just before Scorpius started his third year at Hogwarts.
The Greengrass family is one of the Sacred 28, a pureblood family over many generations.
Astoria, Oregon and Manhattan's luxury Waldorf-Astoria hotel both take their names from members for the wealthy American society family the Astors. The name communicates the same sort of prominence associated with the Malfoy family. -BB
The spelling of Astoria/Asteria's name was in question because it was given as Astoria by Time Magazine, and as Asteria in the hand-drawn family tree shown in the ITV documentary and on Jo's website. Jo also pronounces it Astoria, and it appears as Astoria in the Cursed Child play.