You can go now and base her size off of previous baby weight gain experince...this is number 3 right???? I would definately order something loose on the bottom...stay away from super form fitting dresses...there are so many styles out there....look around and get advice from the bridal store...have nothing to fear!!!
if you get your dress at a place that caps alterations...have her order the biggest size she wants...and when it comes in, they can size it accordlingly. I've been in bridal parties before with girls who had a baby a few months before the wedding. this is what they did.
I would have her buy a dress now or within 2 months and then have it taken in after the baby. It is always easier to have a dress taken in then have it taken out. You know?
