A.B.
It depends on how you think she will react. You know her; is this her normal behavior, being mean and accusatory? If it is, there's not much point in a confrontation (there isn't much point in confrontation anytime). Your HUSBAND should tell his mother that she can't come because this is between the two of you. And, although I hope your baby is healthy (and I'm sure it will be!), if, God forbid, something is wrong, and it shows in the ultrasound, do you really want her there to accuse you? Let your husband reign in his mother. You stay out of it.