After getting you pregnant, Draco despises you. When professor Snape finds out he confronts Draconand that's where they had a delighted conversation where Draco tells Sanpe to "kill him" because he "doesn't care" through the pregnancy Draco begins to care for you and his child. When Voldemort finds out he begins to use this against Draco to make him comply. After Draco threatened to begin help Harry defeat him, Voldemort takes you by the neck and that's were the rest happens

Draco:"kill her and the baby.." Snape stares at him in shock Drack:"what do I care?" In the future Voldemort:"I don't care who dies! But since you do.. indugle me" *You scream in pain as Voldemort hurts you" Voldemort:"and I just might spare the mother of your child" you continue to scream and cry in pain Voldemort:"kneel! Get on your knees" Voldemort points the wand to your neck Draco kneels Everyone stares in disbelief