Hayden Panettiere is pregnant in real life, which is indirectly affecting her career on every single level. Most actresses unfortunately have to deal with this when they become pregnant, especially when they're shooting a major television show or a soap opera. As the lead of 'Nashville', Hayden's character will obviously be affected by Hayden's own looks. If Hayden gains weight, her 'character' gains weight. If Hayden is pregnant, her character is... pregnant?
Apparently, the show's writers are thinking of going in that direction, instead of using expensive CG and camera angles to hide her pregnancy. Usually, when the show can make it work, they try to.
With the examples of Kerry Washington on Scandal or Claire Danes on Homeland, there are methods of hiding pregnancies during TV shows, especially when the actresses aren't that far along. But it would be extremely difficult to hide Hayden's pregnancy when they resume filming because she will be well past her first trimester at that point.
TV Line's Michael Ausiello - also known as the spoiler king of TV shows - has revealed that Juliet will be heavily pregnant on Nashville next season, reflecting her actress' situation. Plus, ABC has already dealt with actress pregnancies with Scandal and Ginnifer Goodwin on Once Upon A Time. Having to deal with it on a show with a lower budget than Scandal and Once Upon A Time should actually be easier for them, although they may really be under tighter financial constraints. But now, with Juliet's pregnancy, there won't actually be any awkward camera cuts or throwaway angles. Instead, the writers will get to fully incorporate Hayden's pregnancy into the show, and make it a part of the narrative storytelling.