Why are they hiding....

[playfelt]

Sine they have waited this long to say something and still aren't, I would be using the calendar and picking a date about a month after she would be due and advertising to replace the child.

My guess is she is afraid you will turf them right away and it is possible that they did mention the pregnancy in the first few interviews and immediately got turned down so they planned to keep it to themselves as long as possible. And confronting her might get you that answer.

Having dealt with several pregnant families in the last few years my gut says they will say they will stay but then change their minds at the last minute or a month or two into the leave once her strength comes back ie 6 weeks.

You would have every right to sign on a new family and then when she starts talking about it finally let on at that time that you have known all along but were waiting for her to say something and when she didn't you felt you had to protect your business so you are very sorry but that you have replaced the child with a new one and hope big sister will have fun home with mom and baby on mat leave.