The Surrogate Mother by Freida McFadden

But after years of failed infertility treatments and adoptions that have fallen through, it seems like motherhood is not in her future. That is, until her personal assistant Monica makes a generous offer that will make all of Abby’s dreams come true.

Or all of her nightmares.

Because it turns out Monica isn’t who she says she is. The woman now carrying Abby’s child has dark, twisted secrets.

And she will stop at nothing to get what she wants.