Season seven ends with Cersei tricking the good guys into thinking she's sending her armies to help fight the White Walkers, while in fact she plans to wipe her enemies out using the Golden Company mercenaries. Her reason for the betrayal is to protect her family — which, after Jaime's dramatic exit, leaves only her and her unborn child.
Cersei would do just about anything for her children, so why is she drinking in the season eight trailer? Sure, this queen loves her wine, but Cersei refuses to drink with Tyrion in the season seven finale which immediately clues him in to her pregnancy. The trailer also only shows Cersei in a way that keeps her stomach hidden. Will something happen to her baby? Was she lying the whole time about being pregnant?