I am so sorry you have such a MIL. I think that is an absolute terrible thing to say!! I cannot imagine ANY grandmother saying such a horrible thing. It is obvious she is only concerned with herself. She is only thinking about how she believes it is going to make her look. And all that says is that she is a very insecure woman. Since she is insecure ..... this may be her way of getting attention from your husband, since you are pregant I am sure you have been getting all of his attention lately, maybe she is just jealous. You know what they say....negative attention is better than no attention at all! Good grief, what a wanch! DO NOT let her upset you, she is not worth it!!! Sounds like she is trying to push your buttons .... don't give her the satification.
