In this scene, we learn a little more about the working relationship between Vincent and his werewolves.
From Inside the Grey House:
Charlie took another look at the man, wondering if the ex-waiter from The Red Thread was indeed still human.
Rebecca leaned back against the desk, chewed on her lip and plunged ahead. “I’m pregnant.” Vincent raised an eyebrow; Markus made a noise and Charlie blushed. “Do you remember how my mother was when she was pregnant with me, sir?”
Vincent nodded his head once, slowly in affirmation. Rebecca’s mother became rather dangerous in her later months. “You’re leaving then?”
“As long as you approve.” There was a hint of sarcasm in her voice.
Vincent snorted then smiled. “And Charlie?”
“I’d like to go with her, until she sends me back.” Rebecca’s mom hadn’t been able to stand her husband in the last two months of pregnancy and he had been too much of a risk at that point as well. Charlie was warned it could be the same with him.