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Pulmonary hypertension, or high blood pressure in the lungs, could be a very dangerous—potentially life-threatening—condition during pregnancy. When you’re pregnant your body goes through a multitude of changes that affect all of your organ systems, including your cardiovascular system. First, the volume of blood that gets pumped throughout your body increases by as much as 50%. Additionally, due to hormones like progestin and relaxin, the elasticity of your blood vessels increases. This means that your systemic vascular resistance, or the tightness of your blood vessels, decreases. This, in pregnancy, is what leads to a backup of blood and fluid in your lower extremities (foot and ankle swelling, anyone?).
Normal changes in pregnancy that could lead to pulmonary hypertension:
- Increased volume of blood
- Increased flexibility of blood vessels
Because of both the increase in blood volume and the decrease in systemic vascular resistance, your heart has to work extra hard to keep up. Pulmonary hypertension, or increased blood pressure in the blood vessels of the lungs, comes about when the heart has trouble pumping all that blood throughout your body. Not only does blood and fluid backup in your feet and ankles, but it could also back up in your lungs. This not only compromises your growing fetus’s blood supply, but also compromises your ability to fully oxygenate the blood that powers your own muscles and organs.
There are a number of reasons why your heart may have trouble keeping up. In addition to the normal changes that occur in pregnancy, pre-existing disease could be a contributing factor. For example, if you have any type of issue with your heart before pregnancy, you should be carefully monitored for possible pulmonary hypertension. Heart issues can include, but are not limited to, congenital heart diseases like atrial septal defect or patent ductus arteriosus, and left-sided heart conditions like mitral or aortic valve disease or left ventricular dysfunction.
Possible causes of pulmonary hypertension in pregnancy:
- Heart can’t keep up with load of increased blood volume
- Heart can’t pump hard enough to overcome the increased elasticity of blood vessels
- Certain drugs or infections
- Pre-existing heart condition
- Pre-existing lung condition
- History of thromboembolic disease
- History of collagen vascular disease*
Another pre-existing condition that could lead to pulmonary hypertension in pregnancy would be any type of lung or respiratory disease. These could be any of the obstructive lung diseases like asthma or COPD, or even pulmonary fibrosis (stiffness and scarring of the lungs) from prior pneumonias, rheumatoid arthritis, or environmental insults like cigarette smoking. Pulmonary fibrosis can also be idiopathic, which means we don’t actually know the cause.
A history of thromboembolic disease is yet another risk factor for pulmonary hypertension. If you have experienced a blood clot (thrombus), particularly one that has traveled to another part of your body, you should be carefully monitored. Collagen vascular diseases, like lupus, scleroderma, rheumatoid arthritis, and Sjogren syndrome also put you at increased risk.
Symptoms of pulmonary hypertension include:
- Shortness of breath
- Dizziness or fainting
- Pain or pressure in your chest
- Lower extremity swelling
- Increased heart rate
- Heart palpitations
- Bluish discoloration of lips
Women who have pulmonary hypertension in a non-pregnant state are generally counseled against becoming pregnant. However, if you do become pregnant there are some things to keep in mind. First, the riskiest times for the occurrence of adverse events are the peripartum period (shortly before, during, and after giving birth) and the postpartum period (within about 2 months after giving birth). Second, a Caesarian section will be the preferred method of childbirth over vaginal delivery to reduce complications. Third, epidural anesthesia will be preferred over general anesthesia. Finally, medications such as prostacyclin (injected or inhaled) and phosphodiesterase inhibitors can be used to manage pulmonary hypertension in pregnancy. If you have a thromboembolic disorder, low molecular weight heparin may also be used as medication therapy.
To recap, pulmonary hypertension is increased blood pressure in the blood vessels of your lungs. This condition is very dangerous—potentially deadly for both mother and fetus—in pregnancy. Possible causes include normal changes that accompany pregnancy as well as pre-existing conditions, infections, medications or other drugs that compromise heart, lung, or blood vessel function. Although there are medications that can treat pulmonary hypertension, if you have pulmonary hypertension in a non-pregnant state you will most likely be counselled against getting pregnant.
*It is very important to tell your doctor if you have a pre-existing condition like the ones listed above. Many times the symptoms of pulmonary hypertension can mimic some of the normal effects of being pregnant.