A Caress of Twilight - Laurell K. Hamilton

"I am Princess Meredith, heir to a throne-if I can stay alive long enough to claim it."

After eluding relentless assassination attempts by Prince Cel, her cousin and rival for the Faerie crown, Meredith Gentry, Los Angeles private eye, has a whole new set of problems. To become queen, she must bear a child before Cel can father one of his own. But havoc lies on the horizon: people are dying in mysterious, frightening ways, and suddenly the very existence of the place known as Faerie is at grave risk. So now, while she enjoys the greatest pleasures of her life attempting to conceive a baby with the warriors of her royal guard, she must fend off an ancient evil that could destroy the very fabric of reality. And that's just her day job. . . .