Risk factors Factors that may increase the risk of developing motion sickness or increase the severity of symptoms include the following: Poor ventilation (eg, with exposure to fumes, smoke, or carbon monoxide) Emotional factors (eg, fear, anxiety about travel or the possibility of developing motion sickness) Migraine headaches Vestibulopathy (such as labyrinthitis) Hormonal factors (eg, from pregnancy or use of hormonal contraceptives) Genetic factors may also increase susceptibility to motion sickness (1).