The Memory Child by Steena Holmes
What a ride! This was by far the most terrifying book I've ever read. And I can't even tell you what happens. Just trust me.
You've got a high powered couple expecting their first child. Brian is over the moon, Diane is understandably nervous. She never wanted to have children. But they are clearly in love and it's a happy time. But once Diane has the baby with her she is happy, except that Brian is off in London. Luckily she has her nanny.
The story jumps from Diane's perspective in the present and Brian's in the past it's like this building crescendo that knocks you off your feet.
This is Steena Holmes' best book so far. Keep it up, girl!