Neuron Structure. Your brain is made of approximately 100 billion nerve cells, called neurons. Neurons have the amazing ability to gather and transmit electrochemical signals -- think of them like the gates and wires in a computer.
Most doctors will only consider chronically low blood pressure as dangerous if it causes noticeable signs and symptoms, such as: 1  Dizziness or lightheadedness. 2  Nausea. 3  Fainting (syncope)  Dehydration and unusual 1  thirst. Dehydration can sometimes cause blood pressure to drop.  Lack of 1  concentration. Blurred vision.  Cold, clammy, pale skin.
Low blood pressure is common in early pregnancy because hormonal changes cause the blood vessels to open wider, meaning blood isn't pumped through the body with as much power. This can cause pregnant women to feel many of the symptoms of low blood pressure, including unsteadiness and even fainting.