Bianca Balti has been a long-term face of Dolce and Gabbana, so I feel that they made the right decision to put her in the show despite her being six months pregnant. To answer your second question, models aren’t typically allowed to show any emotion in shows as it can be distracting/take the attention away from the clothing. However Bianca’s expressions on the runway were appropriate as being pregnant is a happy and emotional experience. In her case it probably would have looked bad if she showed no emotion.