Hypertensive Disorders of Pregnancy
Nov 10, 2021
Hypertension is the fancy word for high blood pressure, a common condition where the long-term force of the blood against your artery walls is strong enough that it may cause health problems. Hypertensive disorders of pregnancy are health issues associated with high blood pressure in pregnancy, and they are the leading cause of maternal death due to long-term health complications, such as cardiovascular disease. They can also impact the health & safety of the developing fetus. Listen to the full podcast to learn more about the main types of hypertensive disorders of pregnancy, how they are diagnosed, treated, and how they might be prevented!
There are basically four major types of hypertensive disorders that can occur in pregnant people. These are:
- Chronic Hypertension (pre-existing)
- Gestational Hypertension
- Preeclampsia, Eclampsia & HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets)
- Preeclampsia Superimposed on Chronic Hypertension
- Chronic hypertension is defined as hypertension that is present prior to pregnancy, is present on at least two occasions before the 20th week of gestation, or persists longer than 12 weeks postpartum.
- It can be primary (meaning we don’t really have a specific reason for it) or secondary to an underlying disease (ex. chronic kidney disease)
- Up to 20% of individuals with chronic hypertension will go on to develop preeclampsia compared to only 1% of the general pregnant population, which is why it should be addressed and treated, ideally before pregnancy when it is safer to use a wider range of blood pressure medications.
- Gestational hypertension is essentially high blood pressure that develops in pregnancy (after 20 weeks) but is not associated with any adverse features that we see with preeclampsia.
- Between 10%-25% percent of pregnant people with gestational hypertension may ultimately develop signs and symptoms of preeclampsia.
- Gestational hypertension usually resolves by 12 weeks postpartum, but if it persists beyond 12 weeks postpartum, the diagnosis is "revised" to chronic hypertension that was masked by the natural decrease in blood pressure that occurs in early pregnancy.
Preeclampsia, Eclampsia & HELLP Syndrome
- Preeclampsia is not a very common condition, affecting on average 1-2% of pregnancies, and refers to the new onset of high blood pressure resulting in organ damage (often the kidneys & liver), typically developing after 20 weeks of gestation in a patient who previously had normal blood pressure.
- The organ damage is typically assessed by looking for abnormalities on blood work and for protein spilling into the urine.
- Eclampsia refers to the occurrence of a seizures due to severely elevated blood pressure in a woman with preeclampsia, without other neurologic conditions that might account for the seizure
- HELLP syndrome is named after the laboratory changes we see in pregnant people who develop this disorder. It stands for Hemolysis (breakdown of red blood cells), Elevated Liver enzymes, Low Platelets.
- HELLP syndrome is thought to be a subtype of preeclampsia with severe features in which hemolysis (breakdown or destruction of red blood cells), elevated liver enzymes, and low platelets are the predominant features, rather than high blood pressure, central nervous system, or kidney dysfunction (although the latter do occur).
Chronic hypertension with Superimposed Preeclampsia
This is a condition that occurs in women who have been diagnosed with chronic high blood pressure before pregnancy, but then develop worsening high blood pressure and protein in the urine or other health complications during pregnancy.
Although the numbers of pregnant people who develop these disorders aren’t extremely high (it is estimated that the global incidence of preeclampsia ranges from 1%-5.6%, while the incidence of eclampsia ranges from 0.1%-2.9%), they can have significant impacts on maternal and fetal health both in the short and long term, so we need to be aware and treat according to guidelines.
Who is at risk of developing gestational hypertension and/or preeclampsia?
Although the mechanisms of what causes these conditions is still not thoroughly understood, experts have found that it is associated with the improper implantation and development of blood vessels in the early growth of the placenta, as well as maternal factors.
The increased maternal risk factors for developing preeclampsia include:
- A previous history of preeclampsia
- Pre-existing conditions like diabetes or chronic hypertension
- Certain auto-immune disorders
- Pre-pregnancy BMI of greater than >25
- Underlying chronic kidney disease
- Multifetal pregnancy (ex. twins means two placentas, which means twice the risk!)
- Never having been pregnant before (due to new immune exposure to paternal antigens)
- Family history of preeclampsia
- A prior pregnancy with complications such as growth restriction, abruption, or stillbirth
- Advanced maternal age
- Use of assisted reproductive technologies
Diagnosis, Treatment and Prevention?
Diagnosis is a combination of:
- Regular blood pressure testing: several times during one visit to establish if and how consistently it is elevated
- A physical exam: symptoms such as visual disturbances (typically seeing spots or stars), new headache, chest pain/shortness of breath, pain in the upper right side of your abdomen (where your liver sits) and new swelling in hands and feet can be (but isn’t always) associated with preeclampsia. They will also check for “hyperactive” reflexes.
- Bloodwork: used to look for signs if your blood pressure is starting to cause damage to your organs (particularly your liver and kidneys)
Based on these three factors, an individualized treatment/management plan is crafted. If your blood pressure is found to be significantly and consistently elevated, two medications that are routinely used include labetalol (a beta-blocker) and nifedipine (a calcium channel blocker). Your fetus will also be routinely monitored through ultrasounds and nonstress tests to make sure it is growing well!
If you have underlying health conditions that put you at an increased risk, we recommend starting on baby aspirin in your first trimester. For those with pre-existing or chronic hypertension, making sure your blood pressure is well controlled coming into pregnancy is important. And lastly, if you are trying to conceive and you’re carrying extra weight, improving your diet and increasing physical activity will also reduce your risk of developing gestational hypertension and pre-eclampsia.
Tune in to today’s podcast where Dr. Sarah discusses all of the above in more detail and breaks down this rather complex medical condition, and as always remember to consult your healthcare provider for a diagnosis and treatment specific to you!
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