Sudden bout of dizziness in pregnant women is more common with abnormal blood pressure, abnormal blood sugar, cervical spondylosis and so on. 1. Abnormal blood pressure: such as increased blood pressure, low blood pressure, may lead to a sudden burst of dizziness in pregnant women. Abnormal blood pressure is generally associated with poor dietary habits and lifestyle; if the blood pressure continues to rise, it should be alerted to pregnancy hypertension. 2. Abnormal blood glucose: mainly including hypoglycemia, hyperglycemia, rapid decrease or rapid increase of blood glucose level may lead to sudden dizziness of pregnant women. If the blood sugar is high for a long time, the possibility of gestational diabetes should be excluded as soon as possible. 3. Cervical spondylosis: with pregnant women sitting for a long time, or due to long-term attention to posture, resulting in cervical spine compression. When the condition is serious and causes insufficient blood supply to the brain, there will be a sense of dizziness. Pregnant women suddenly a burst of dizziness, may also be due to sudden emotional excitement or heart rate increase due to, it is recommended to go to the hospital to consult a doctor, clear causes and then symptomatic treatment.