Severe pregnancy sickness at night may have some relation to gastrointestinal reactions related to elevated blood HCG, but it may also have some relation to oily diet and mental anxiety at night. Pregnancy is characterized by a series of gastrointestinal reactions due to elevated blood HCG levels. During the daytime, pregnant women are relatively more distracted, and it is easy to reduce gastrointestinal reactions due to the interference of other things. In the evening, the vagus nerve of pregnant women is excited and more focused, so it may lead to the phenomenon of severe vomiting at night. A greasy diet at night can also lead to severe nighttime vomiting, which is usually relieved after dietary adjustments. When a pregnant woman is free at night, she may think more, leading to mental anxiety, which may cause severe pregnancy vomiting. There are many reasons for severe nighttime vomiting, you need to go to the hospital in time, under the guidance of the doctor to take standardized treatment, do not use private medication, so as not to cause danger.