A maternity spell is a spell linking its victim to its caster. If the link is broken without great care, from a close distance, the victim will die. When linked to each other, the survival of the victim is completely dependent on the caster's, and anything physical that happens to the caster will happen to the victim. The caster is always able to sense that the victim is alive on the other end. This spell requires great power and skill to perform, and because the link has to be maintained at all times, constantly draws on the caster's Han. It deprives the caster of the power needed to perform even the simplest of magics.
Nicci, a Sister of the Dark and one of the most powerful sorceresses in existence, cast the maternity spell on the Mother Confessor Kahlan Amnell to convince Kahlan's husband, Richard Rahl, to come with her to the Old World. It was taught to Nicci by the venerated Sister of the Light, Lidmila.
In the Legend of the Seeker television show, the maternity spell can only be broken by the caster or by the magical reestablishment of the maternal bond between the victim and his or her real mother.