Low blood pressure, or hypotension as it is also known, is any reading lower than 90/60 mm Hg, according to the National Heart Lung and Blood institute. The body is very sensitive to changes in blood pressure. Special cells in the arteries can sense if the blood pressure begins to rise or fall. When this happens, the cells trigger the body to try to bring blood pressure back to normal. Certain factors or conditions that disrupt the body's ability to control blood pressure cause hypotension.
Medical Conditions
Both the American Heart Association and the National Heart Lung and Blood Institute concur that certain heart conditions are contributing factors for low blood pressure. These include heart attack, heart failure, heart valve problems and a low heart rate, which prevent the body from circulating a sufficient amount of blood. Thyroid disorders, low blood sugar and diabetes, which are disorders of the endocrine system, may result in hypotension, as well.
Being Pregnant
Low blood pressure is a common problem among pregnant women, especially during the first 24 weeks of pregnancy when the circulatory system is quickly expanding, according to MayoClinic.com. The bottom, or diastolic, number, which measures the pressure when the heart is at rest between beats, usually drops by five or 10 points, while the top, or systolic, number, which measures the pressure while the heart is pumping blood, drops a bit further--as much as 15 points.
Dehydration and Its Complications
Dehydration alone is dangerous, resulting in fatigue, weakness and dizziness. The loss of blood pressure comes when hypovolemic shock, a life-threatening complication of dehydration, sets in. MayoClinic.com explains that dehydration can cause a reduction in blood volume, resulting in a sudden drop in pressure. This results in a loss of oxygen reaching the tissues of the body. This is hypovolemic shock, and when a person does not seek treatment, it may become severe, resulting in death within a matter of minutes or hours.
Medications
Medications such as diuretics, beta-blockers, tricyclic antidepressants, drugs for the treatment of Parkinson's disease, drugs for erectile dysfunction and drugs for high blood pressure can all result in a sudden drop in blood pressure, according to the American Heart Association. Other medications can cause low blood pressure, as well, and patients should speak to their doctors if they experience this side effect.
Septic Shock
Septic shock is a condition that occurs when bacteria from an infection in the body leaves that site and enters the bloodstream. The most common areas of infection include the lungs, abdomen and urinary tract, according to the American Heart Association. A drop in blood pressure occurs when the bacteria begins producing toxins that affect the blood vessels.
