First Born (2006)

Laura (Academy AwardŽ nominee, Elisabeth Shue) seems to live the quintessentially perfect life: all that seems to be missing for Laura, however, is a baby.

But be careful what you wish for.

Laura soon discovers that she's pregnant, and after moving to the suburbs, she finds herself feeling alone, and increasingly isolated in their large, secluded home in the country. When the baby is born, it quickly becomes apparent that being a mother is more challenging than Laura ever imagined, as she gradually begins a slippery downward spiral into postpartum depression. Saddled with the primal maternal need to protect her infant at all costs, Laura suddenly questions her ability to do so as well as her sanity. From a rat-infested basement with a mysterious diary found in its walls, to the peculiar new nanny that Steven employs to assist his increasingly erratic wife, FIRST BORN abounds with the creepy aspects and haunting details of a first-rate psychological thriller.

Source: First Look Home Entertainment