I recently got engaged, and I want my sister to be my maid of honor. But come wedding time, she is going to be very pregnant, and I'm not sure that she will be able to wear the bridesmaid dresses that I've picked out. How should she dress?
You simply need to find a dress for her that she'll be comfortable in. You could choose an Empire-waist dress -- leaving lots of room for a pregnant tummy -- and you can even have extra material sewn in for her if she needs it. Or, have her choose a maternity dress in the same color or fabric as the other bridesmaid dresses. Also, on the wedding day, make sure there's a chair that she can use during the ceremony, so she won't have to stand the entire time. The point is having your sister in your wedding party. As long as she walks down the aisle as a person of honor (in a dress that fits her comfortably), that's all that matters!
Bridal Party Fashion
Basics for Bridesmaids