Quick summary: she performed fellatio on the guy and swallowed the sperm. Briefly after, the ex-boyfriend stabbed her in the abdomen through which two internal wounds were created. One must have opened a connection from her stomach to her internal genital organs (ovaries or uterus, it isn't specified) that allowed the sperm from her stomach to drop into and thus fecund an egg.
Don't ever doubt lifes's survivability.