All 5 Uses

conceive
in
Breaking Dawn, by Meyer
(Edited)

Though Edward clearly—if inconceivably—preferred me, I wouldn't be able to help making comparisons.
Book 1 *

inconceivably = in a manner that is not able to be understood or imagined

standard prefix: The prefix "in-" in inconceivably means not and reverses the meaning of conceivably. This is the same pattern you see in words like invisible, incomplete, and insecure.
Of course Rosalie could not conceive a child, because she was frozen in the state in which she passed from human to inhuman.
Book 1

conceive = create through pregnancy
How could we know that a human was able conceive a child with one of us—
Book 2 *
She conceived, carried, and gave birth to Renesmee while she was still human.
Book 3

conceived = became pregnant
“Half mortal, half immortal,” Aro announced to him and the rest of the guard without turning his enthralled gaze from Renesmee. Conceived so, and carried by this newborn while she was still human.
Book 3

conceived = created through pregnancy

Definitions:

(1) (conceive as in: conceive the idea)
to originate, understand, or imagine
(2) (conceive as in: conceived their first child)
become pregnant or fertilize an egg
(3) (meaning too rare to warrant focus)