Often we see photos like this and it’s the work of a husband who doesn’t usually spend that much time in the kitchen, but is being ‘helpful.’ Forgetting to take a plastic tray out of the oven before you turn it on is a classic case of not really paying attention to what you’re doing.
So, it’s not really a surprise that it’s something that pregnant women are prone to do as well. This is going to be one hell of a cleanup job and I can imagine that it smells terrible. In fact, it’s probably not safe for her to be around the fumes. She should let her partner clean it, just in case.