Whether your blood pressure condition pre-existed your pregnancy or started in pregnancy (gestational), your doctor will work with you on how to best address your blood pressure issues to keep you and your growing baby safe. High and low blood pressure can happen in pregnancy for a variety of reasons, sometimes as a complication of pregnancy and other times due to a pre-existing condition. When high blood pressure develops after 20 weeks gestation, it is called gestational high blood pressure or hypertension. Regardless of the cause, your health care provider will closely monitor your blood pressure throughout your pregnancy and treat your specific condition as needed. Below we explore the typical causes of high and low blood pressure in pregnancy, including preeclampsia, a serious high blood pressure condition. We will also review risk factors, symptoms, treatment options, and coping strategies.
High Blood Pressure
High blood pressure in pregnancy is a serious complication that your doctor will track at each prenatal visit. In pregnancy, both gestational high blood pressure and chronic hypertension (elevated blood pressure prior to 20 weeks gestation) carry the risk of developing into preeclampsia. All types of high blood pressure can share the same symptoms, including:
DizzinessHeadachesLightheadednessPounding feeling in the head or chest
Other times, there are no discernable symptoms other than a high reading, which is why it’s critical to get regular prenatal exams where your blood pressure will be checked routinely. The appearance of high blood pressure or a sudden spike in blood pressure can be dangerous to both mother and baby.
Preeclampsia
High blood pressure during pregnancy is most often associated with preeclampsia, which is a serious pregnancy complication that causes elevated blood pressure. It can also cause damage to other organ systems, including the liver and kidneys. What separates preeclampsia from regular high blood pressure is the fact that it only happens during pregnancy, and women with otherwise normal blood pressure levels can be diagnosed with this condition. Plus, just like gestational high blood pressure, it normally goes away after the postpartum period. Risk Factors Risk factors that increase the odds of developing preeclampsia in pregnancy include any of the following:
It’s your first pregnancyYou had preeclampsia in a previous pregnancyYou had chronic hypertension before week 20You are BlackYou’re carrying multiple fetusesYou have obesityYou have certain health conditions, including type 1 or type 2 diabetes, lupus, and chronic kidney diseaseYou became pregnant using in vitro fertilization (IVF), egg donor, or donor inseminationYou are over 40
Symptoms In addition to developing high blood pressure after week 20, some of the more common signs of preeclampsia include:
Abdominal pain, typically high on the right side of the bellyBlurred vision, temporary loss of vision or light sensitivity Decreased urine outputDifficulty breathingExcess protein in the urineHeadaches that are severe, more frequent than normal, and/or don’t go awayNausea or vomitingSudden weight gainSwelling of the face and hands
Some women do not experience any noticeable symptoms of preeclampsia (or gestational hypertension), making regular prenatal check-ups all the more important to ensure any changes in blood pressure are monitored throughout pregnancy. Additionally, while rare, some women develop preeclampsia after delivery, typically within 48 hours, but it can occur within six weeks of having a baby. This is called postpartum preeclampsia. It shares the symptoms of preeclampsia and is treated similarly. Treatments for preeclampsia follow similar protocols for chronic hypertension, which are discussed in detail below.
Chronic Hypertension
High blood pressure before pregnancy or that occurs before the 20-week mark is typically referred to as chronic hypertension. In either chronic or gestational hypertension, your doctor will likely assess your readings to determine the stage of hypertension. According to the American Heart Association, there are five blood pressure classifications, including three stages of hypertension:
Normal: Systolic levels less than 120 mmHg AND diastolic levels less than 80 mmHgElevated: Systolic levels ranging from 120 to 129 mmHg AND diastolic levels less than 80 mmHgStage 1 Hypertension: Systolic levels ranging from 130 to 139 mmHg AND/OR diastolic levels at 80 to 89 mmHgStage 2 Hypertension: Systolic levels 140 mmHg or higher AND/OR diastolic levels 90 mmHg or higherStage 3 Hypertensive Crisis (consult your doctor immediately): Systolic levels higher than 180 mmHg AND/OR diastolic levels above 120 mmHg
At each prenatal visit, your doctor will take your blood pressure and make a note of it to compare to previous readings. If you are in stage 3, you will need immediate care. Uncontrolled stage 3 hypertension can induce a hypertensive crisis, which can cause serious complications including organ failure, heart attack, and stroke. If you fall into one of the other hypertension categories (stage 1 or 2) or have elevated blood pressure, you may be asked to monitor your blood pressure from home or go into the office for more frequent blood pressure readings. This will also be the case for those diagnosed with preeclampsia.
High Blood Pressure Complications
While many women who have hypertension prior to pregnancy do very well, there are some potential complications to be aware of. You and your doctor will come up with a plan to manage your symptoms. Additionally, women who have chronic or gestational hypertension are at risk of developing preeclampsia in their second or third trimesters. Physiologically, the effects of progesterone typically lower blood pressure during the first and second trimester of pregnancy, according to Robert Atlas, MD, an OB/GYN who specializes in high-risk pregnancy issues at Mercy Medical Center in Baltimore, MD. Blood pressure will return back to pre-pregnancy levels in the third trimester. Additionally, he says the following are some of the more common complications associated with high blood pressure in pregnancy:
20% to 30% chance of developing superimposed preeclampsia, if you have hypertension prior to pregnancyIncreased risk of preterm birthIncreased risk of fetal growth problems, which may result in low birth weightWomen who have underlying kidney problems have an even higher risk of blood pressure complications in pregnancy
Treating High Blood Pressure
Similar to the treatment approaches for hypertension in non-pregnant patients, women who have high blood pressure prior to pregnancy can manage symptoms of hypertension through medication and lifestyle modifications. These are the same treatments used with preeclampsia as well. Dr. Atlas says most mothers with elevated blood pressure will generally be treated with medications to lower the blood pressure. “We use Labetalol and Nifedipine often for patients as they have generally been shown to be safe in pregnancy,” he explains. That said, Dr. Atlas does point out that some people may be on medications prescribed by internists or renal doctors that are not safe to take in pregnancy. “Medications such as ACE and ARB inhibitors can be potentially harmful to the developing fetus,” he explains. In addition to medication, treating high blood pressure during pregnancy involves:
Eating a healthy diet rich in fruits, vegetables, lean protein, and complex carbohydratesLimiting sodiumExercising regularlyIf overweight, limiting weight gainManaging stress levelsAvoiding alcoholQuitting smoking
If high blood pressure spikes too high and does not respond to medication and/or lifestyle accommodations, other possible treatments include bed rest and induction of labor. Particularly with preeclampsia, if a woman’s pressure is too high and her baby is viable (especially when close to full term), inducing labor will be considered.
Low Blood Pressure
Normal blood pressure is a reading that is anything less than 120 mm Hg systolic and 80 mm Hg diastolic. There is no official barometer for distinguishing “low” blood pressure from normal, and within limits, lower readings are usually a good thing. In fact, it’s common to have periods of low blood pressure during pregnancy, especially in the first 24 weeks and/or if you have had low blood pressure prior to becoming pregnant. Generally, low blood pressure is not a concern unless symptoms accompany it. “If a person who has low blood pressure does not have any symptoms, we would not be worried about that individual, but if a person who has low blood pressure is symptomatic, (i.e., dizzy, lightheaded, blurred vision, etc.) there would be some potential issues to be concerned about,” explains Dr. Atlas.
Low Blood Pressure Complications
While many women who have low blood pressure prior and during pregnancy do not have any related issues, there are some complications to be aware of. Some symptoms of low blood pressure include:
Blurred visionCold, clammy, pale skinDehydration and unusual thirstDepressionDizziness or lightheadednessFatigueLack of concentrationNauseaRapid or shallow breathing
One of the most concerning complications is dizziness because it can lead to fainting, falling, and injury, secondary to the fall. Additionally, research has shown a link between low blood pressure and increased symptoms of morning sickness.
Treating Low Blood Pressure
The main goal in treating low blood pressure during pregnancy is symptom reduction, especially if you are experiencing dizziness and fainting. For the most part, many people can manage symptoms of low blood pressure with lifestyle modifications, such as:
Staying hydrated Consuming enough calories to support you and your babyAvoiding standing for long periods of timeMoving slowly from a supine or prone position to a standing position
Blood pressure tends to be lower when a person is at rest and can cause blood to pool in the legs, so it’s important to move positions or get up from a seated or reclining position slowly to avoid the onset of symptoms, such as dizziness or fainting. “If a patient is on a medication that may cause low blood pressure, we would recommend discontinuing the medication,” explains Atlas. Like high blood pressure, treating low blood pressure with medication during pregnancy is only recommended when absolutely necessary—and only with medications known to be safe during pregnancy.
A Word From Verywell
If you have low or high blood pressure prior to pregnancy, it’s always a good idea to schedule a preconception appointment with your doctor to discuss any complications or concerns you may have relating to conception and pregnancy. This is also the best time to collaborate on a plan to help manage your symptoms when you do become pregnant. If you develop low or high blood pressure (including preeclampsia) while pregnant, the same is true. You’ll want to work with your doctor to effectively manage your symptoms to keep both you and your baby safe.
