Typically, when selecting maternity clothing, you choose the same size as you would pre-pregnancy. That means that if you’re usually a size large, you would choose a size large in maternity clothing as well. This isn’t always the case, as everyone’s bodies change differently. It is best to consult the sizing guide and/or try on the items if buying in person. You can even try on the items with a foam bump underneath to see how they will look and feel as your pregnancy progresses further. Remember, though, the items are designed to expand as your belly grows, so they typically will last you for your entire pregnancy and long after.