forgive me, father

Voldemort had wondered what type of passion could make Snape care about a mudblood's life. Assuming it was the act rather than the emotion, he takes advantage of Narcissa Malfoy in order to produce an heir, and to preserve the Slytherin pureblood line. But as we know, he dies on that fateful Halloween night, leaving Narcissa with the child. What becomes of her? *set during GOF*