Hypotension is a medical condition causing a person's blood pressure to drop below below normal levels. The National Heart, Lung and Blood Institute explains that a normal blood pressure is 120/80 or slightly less, while a person with hypotension has a blood pressure of 90/60 or lower. Many causes exist for this, some more serious than others.
Dehydration
Dehydration is a condition that causes the body to lose more water than it takes in. While dehydration can lead to a drop in blood pressure, a variety of factors lead to dehydration. These include fever, vomiting, excessive exercise and overuse of of diuretics. Signs of dehydration, according to the American Heart Association, include dizziness, weakness and fatigue.
Pregnancy
During pregnancy, a woman's circulatory system expands quickly to make room for the extra blood her body is producing, according to MayoClinic.com. This causes her blood pressure to drop, and is most common in the first 24 weeks of pregnancy. Her top number generally drops by five to 10 points, while the lower number generally drops by as much as 10 to 15 points.
Heart Problems
The American Heart Association explains that heart problems such as low heart rate, heart attack and heart valve problems can all cause low blood pressure. These conditions prevent the heart from circulating enough blood through the body, thus resulting in a lower blood pressure.
Loss of Blood
Blood loss from head trauma, internal injuries or any other major injury lowers blood pressure by reducing the amount of blood in the body, explains MayoClinic.com.
Some Medications
The American Heart Association warns that certain medications may cause a drop in blood pressure as a side effect of the medication. This includes heart medications such as beta-blockers, meds for Parkinson's disease, drugs for erectile dysfunction, tricyclic antidepressants and narcotics. If this side effect occurs, a doctor should be consulted.
Allergic Reaction
Some people have severe allergies to substances such as peanut butter, latex products, bee sting toxins and medications such as antibiotics. Allergic reaction can result in a life-threatening condition known as anaphylaxis. This results in breathing problems, hives and swollen throat, as well as a drop in blood pressure. This constitutes a medical emergency.
