Is it permissible for a mother to travel without a mahram to her married daughter residing in Chicago to help her with her first birth, knowing that her husband cannot travel with her and her son is a university student?

A woman is not permitted to travel without a mahram, and there is no necessity for her aforementioned travel. A woman may travel with her husband, or with a mahram, or she should refrain from traveling if she does not find a mahram. If it is established that the travel is essential and she cannot find a mahram, then there is no harm, provided she adheres to the Islamic guidelines regarding dress and speech, and avoids sitting next to men.