High Blood Pressure During Pregnancy
What is High Blood Pressure?
High blood pressure is the leading cause of disability and disease in the world. Almost 50% of adults in the United States have high blood pressure.
Blood pressure is the measurement of the pressure the blood experiences as it rushes through your blood vessels. This is determined by a number of factors, including the amount of blood and how hard your heart pumps it. When this pressure is too high for an extended period of time, you are considered to have “high blood pressure”.
High blood pressure itself is not necessarily dangerous, but the presence of uncontrolled elevated blood pressure dramatically increases the risk of experiencing an adverse event such as a heart attack, stroke, kidney failure, or even death. This is because elevated blood pressure, if left untreated, eventually results in changes to the heart and blood vessels. This includes a thickening of the walls of your heart, making them stiff and increasing the difficulty experienced in pumping blood.
Why High Blood Pressure is Dangerous During Pregnancy
On top of the typical dangers of high blood pressure, there are even more additional risks of the condition while pregnant. It is also possible to develop high blood pressure as a result of your pregnancy due to the changes that occur to the body during this period. Both entering into a pregnancy with high blood pressure and developing gestational high blood pressure can be dangerous to both you and your baby.
One of the main concerns with high blood pressure during pregnancy is the development of preeclampsia. This is a condition unique to pregnancy that affects multiple organs in the body. The main danger of this condition is that, if not monitored and controlled, it may progress into eclampsia which involves multiple organs and can be very dangerous to you and your fetus.
Even isolated hypertension can lead to unwanted consequences during pregnancy, if not properly controlled. This is because the body is working extra hard to pump blood to the organs and this puts extra pressure on the organs, including the baby’s organs.
These possible dangers to your growing baby can include:
- Reduction in your fetus’ growth
- Preterm delivery
- Separation of your placenta from your uterus
This is why it is essential to monitor for, diagnose, and treat high blood pressure during a pregnancy.
Risk Factors for High Blood Pressure During Pregnancy
There are many factors that may put you at an increased risk of developing high blood pressure during your pregnancy. It is important to be aware of these factors in order.
- Pre-pregnancy heart disease (including high blood pressure and high cholesterol)
- Increased age (over 40 years old)
- High blood pressure in a previous pregnancy or hormone altered state
- Family history of heart disease
Patient lab values:
- Systolic and diastolic blood pressure
- Total cholesterol
- HDL-cholesterol (“good” cholesterol)
- LDL-cholesterol (“bad” cholesterol)
Diagnosing High Blood Pressure During Pregnancy
Unfortunately, there are not often symptoms of high blood pressure. This makes it even more dangerous, because you may feel completely fine, but have underlying disease. Therefore, it is essential to seek regular checkups with a healthcare provider throughout your pregnancy where they will monitor your blood pressure and ensure your health is maintained.
In order to diagnose high blood pressure, your healthcare provider will check your blood pressure multiple times, sometimes in multiple different environments (in a doctor’s office, at a pharmacy, at home), in order to ensure the readings are accurate. If you have high blood pressure readings, typically anything greater than 140/90 mmHg, you will likely be diagnosed with high blood pressure. Additionally, it will only be considered to be gestational high blood pressure if you are 20 weeks or further along in your pregnancy.
In order to differentiate between gestational hypertension and preeclampsia, or other conditions, your healthcare provider will likely complete other tests including urine and bloodwork. The main indication that the high blood pressure is due to preeclampsia is upon finding the presence of protein in the urine. In this case, the treatment may be tailored differently in order to prevent the preeclampsia from progressing. Otherwise, with isolated high blood pressure, the diagnosis of gestational hypertension will be made.
In either case, the high blood pressure must be kept under control in order to keep you and your baby safe.
Treating High Blood Pressure in Pregnancy
Many pregnant individuals to not like to take medications during pregnancy. This is because many medications cross through the placenta and reach the baby. While many medications are dangerous to your growing fetus, some are completely safe when taken correctly. However, it is still ideal for most individuals to treat conditions with lifestyle modifications if possible during pregnancy. Fortunately, it is possible for many individuals to reach adequate control of high blood pressure with lifestyle modifications alone.
Lifestyle modifications are often not enough to keep blood pressure under control, and in this case the addition of prescription medication is necessary.
Many of the common medications that treat high blood pressure are not safe for pregnancy. In fact, if you have high blood pressure treated with prescription medications and you get pregnant, your healthcare provider will likely ask you to switch medications in order to protect your growing fetus. The medications that are unsafe during pregnancy include angiotensin converting enzyme (ACE) inhibitors, such as ramipril and captopril as well as angiotensin II receptor blockers (ARBs) such as candesartan and valsartan. These medications are commonly prescribed for high blood pressure but are unsafe for the growing baby particularly during the last two trimesters of pregnancy.
There are, however, slightly less common medications that are safe and effective for treating high blood pressure in pregnancy.
This is not an extensive list, and many other medications can be safe and effective. Your healthcare provider will work with you to decide on the best medication for your particular circumstances.
- Rabi DM, McBrien KA, Sapir-Pichhadze R, et al. Hypertension Canada’s 2020 Comprehensive Guidelines for the Prevention, Diagnosis, Risk Assessment, and Treatment of Hypertension in Adults and Children. Canadian Journal of Cardiology. 2020;36(5):596-624. doi: 10.1016/j.cjca.2020.02.086
- Butalia S, Audibert F, Côté AM, Firoz T, Logan AG, Magee LA, Mundle W, Rey E, Rabi DM, Daskalopoulou SS, Nerenberg KA; Hypertension Canada. Hypertension Canada's 2018 Guidelines for the Management of Hypertension in Pregnancy. Can J Cardiol. 2018 May;34(5):526-531. doi: 10.1016/j.cjca.2018.02.021.
- Duley L. Pre-eclampsia, eclampsia, and hypertension. BMJ Clin Evid. 2008 Aug 14; 2008:1402. PMID: 19445808; PMCID: PMC2907952.