Each year, more than 1,000 Americans are diagnosed with pulmonary arterial hypertension (PAH). According to the Department of Health & Human Services, women are twice as likely to be diagnosed with it. This type of hypertension isn’t the high blood pressure with which you’re probably familiar. It’s a rare type of high blood pressure resulting in a constriction of the arteries that carry blood through your lungs. The symptoms and causes of PAH are very different from those of hypertension, a more common condition.

What Causes Pulmonary Arterial Hypertension?

High blood pressure that occurs in the pulmonary arteries is called pulmonary arterial hypertension (PAH). These arteries carry blood from the heart to the lungs. This type of hypertension is sometimes also called pulmonary hypertension.

PAH begins when the small pulmonary arteries and capillaries begin to narrow, become blocked, or are destroyed. When this happens, blood can no longer flow as easily as it should. This increases blood flow resistance. As a result, the heart has to work harder to move adequate amounts of blood into the lungs.

Pressure will begin to build in the heart and in the arteries as the heart works harder. Eventually, the increased pressure will not be able to overcome the resistance caused by the blockages and narrowed arteries. The right side of the heart, which is the portion responsible for getting blood to the lungs, will grow weak. When that happens, blood flow to the lungs will be insufficient for normal activity. The patient will experience dizziness, shortness of breath, and fatigue as a result. Eventually, the heart may fail entirely.

Types of Pulmonary Arterial Hypertension

Several types of PAH exist. The type you have may determine how it’s treated, how it’s diagnosed, and what your prognosis will be. 

Familial Pulmonary Arterial Hypertension

Researchers have identified one gene that increases a person’s chance for developing PAH. According to the Journal of the American College of Cardiology (JACC), family members with a genetic history of PAH have this mutated gene 80 percent of the time. This type of PAH is called familial pulmonary arterial hypertension. It’s also called heritable pulmonary hypertension. However, having the gene doesn’t mean you’re destined to be diagnosed with PAH. Not every person who has the gene mutation will develop PAH.

Idiopathic Pulmonary Arterial Hypertension

Some people have no family history or gene mutation for PAH. In these cases, doctors may not able to identify an underlying cause for the PAH at all. These patients have idiopathic pulmonary arterial hypertension. 

Secondary Pulmonary Hypertension

In some cases, PAH is the result of another condition or disease. For example, adults who were born with a congenital heart disease (CHD) may develop PAH. Thanks to advances in medications and other treatments, children are now able to survive CHD and live to see adulthood. However, CHD can cause scarring in the pulmonary arteries. That makes blockages and narrowing more likely, which increases the risk for PAH. 

The JACC estimates that 10 percent of adults with CHD also have PAH. One of the CHDs most commonly connected with PAH is Eisenmenger syndrome. This disease results from a large hole between the heart’s two lower chambers.

People who have scleroderma also have an increased risk of developing PAH. Scleroderma is a disease that hardens or thickens the connective tissue that surrounds and supports the skin and organs.

Anemia can also increase a person’s risk for PAH. Chronic anemia conditions, including sickle cell disease, spherocytosis, and thalassemia, have been linked with higher instances of PAH.

Drug-Induced Pulmonary Arterial Hypertension

Several medications, drugs, and toxins have been linked with cases of PAH. Selective serotonin reuptake inhibitors (SSRIs), amphetamines, and fenfluramine (a diet medicine) are among the drugs and medicines that may cause PAH. 

Pregnancy and Pulmonary Arterial Hypertension

Doctors recommend that women who have been diagnosed with PAH avoid getting pregnant. The physical and chemical changes brought on by pregnancy may endanger the mother and the baby if the mother has PAH.

If you’re a woman with PAH, talk with your doctor about your birth control and pregnancy options. Doctors typically recommend women with PAH use a semi-permanent form of birth control, such as an IUD or tubal ligation. Any contraception must be estrogen-free because estrogen can increase the symptoms of PAH.