The sudden appearance of blackness in front of the eyes when the patient is pregnant may have the following factors: 1. Consider that the brain has a transient insufficiency of blood supply, especially caused by ischemia of the internal carotid artery system, and suggest that the patient improve the head vascular examination to see if there is a serious narrowing of the internal carotid artery system. 2. If the sudden appearance of blackness in front of the eyes when the patient is pregnant occurs in the process of position change, such as from the squatting position suddenly If a patient suddenly develops blackness in front of the eyes during a change in position, such as suddenly standing up from a squatting position, a transient blackness in front of the eyes is considered to be caused by postural hypotension, and the patient’s blood pressure in the prone and standing positions can be measured to clarify. If the difference between prone and standing blood pressure is more than 20 mmHg, it is considered to be caused by postural hypotension, so pay attention to whether the patient usually has anemia or low blood pressure, and it is recommended to make timely adjustment.