1. Understanding blood pressure basics
2. What is blood pressure
3. What does my blood pressure measurement mean?
4. How is blood pressure affected by pregnancy?
5. Additional risk factors for high blood pressure
6. Ways to control blood pressure
7. Why is high blood pressure important to track during pregnancy?
8. What are the warning signs of preeclampsia?
9. Why do I need to take my blood pressure at home?
10. How should I set myself up to get an accurate blood pressure measurement at home?
11. What affects blood pressure measurements?
12. Why do I need to take my blood pressure every day / twice a day (or more)
13. What happens if I miss a measurement or forget to take my blood pressure altogether?
14. Why do I need to continue taking BP postpartum?
15. Bloomlife Connects Mom Stories
16. Resources
1. Understanding blood pressure basics
Your body transforms during pregnancy.
Even before you get a hint of a baby bump, your body is undergoing incredible changes internally in order to support the growth and development of your baby.
This transformation includes your cardiovascular system1: affecting how your heart pumps and how much blood will circulate, changing the way your blood vessels deliver this blood supply, and restructuring inputs and output to your newest organ – the placenta – to direct and adjust blood flow to feed your growing baby.
While these changes are a natural and important part of pregnancy – your heart, blood, and blood vessels are now also working to support baby’s growth and development – the effects of these changes on your blood pressure can become risky. For this reason, many women are instructed to keep an extra close eye on their blood pressure throughout pregnancy, especially if they start pregnancy with hypertension (high blood pressure) or are at a higher risk of developing hypertension during pregnancy1.
Even before you get a hint of a baby bump, your body is undergoing incredible changes internally in order to support the growth and development of your baby.
This transformation includes your cardiovascular system1: affecting how your heart pumps and how much blood will circulate, changing the way your blood vessels deliver this blood supply, and restructuring inputs and output to your newest organ – the placenta – to direct and adjust blood flow to feed your growing baby.
While these changes are a natural and important part of pregnancy – your heart, blood, and blood vessels are now also working to support baby’s growth and development – the effects of these changes on your blood pressure can become risky. For this reason, many women are instructed to keep an extra close eye on their blood pressure throughout pregnancy, especially if they start pregnancy with hypertension (high blood pressure) or are at a higher risk of developing hypertension during pregnancy1.
2. What is blood pressure
Blood pressure is all about blood flow2. A blood pressure measurement reflects how much force your blood puts on the walls of your arteries as it flows through. Your arteries are the blood vessels that deliver blood from your heart to your lungs (where red blood cells pick up oxygen) and then carry that oxygenated blood to your organs2.
3. What does my blood pressure measurement mean?
When you take a blood pressure measurement, you will see two numbers separated by a slash3. The first number is called the systolic blood pressure and reflects the pressure on the artery walls when your heart contracts (a heart beat). The second number is called the diastolic blood pressure and reflects the pressure against the artery walls when the heart relaxes between beats. For example, you may measure your blood pressure as 120/80 mm Hg (also read as “120 over 80”)3.
As of 2022, the American College of Obstetricians and Gynecologists (ACOG), uses the following guidelines to categorize blood pressure measurements3:
As of 2022, the American College of Obstetricians and Gynecologists (ACOG), uses the following guidelines to categorize blood pressure measurements3:
What are the guidelines for blood pressure?
- Normal: Less than 120/80 Hg
- Elevated: Systolic between 120 and 129 mm Hg and diastolic less than 80 mm Hg
- Stage 1 hypertension: Systolic between 130 and 139 mm Hg or diastolic between 80 and 89 mm Hg
- Stage 2 hypertension: Systolic at least 140 mm Hg or diastolic at least 90 mm Hg
Source: https://www.acog.org/en/womens-health/faqs/preeclampsia-and-high-blood-pressure-during-pregnancy
Since blood pressure can change naturally throughout the day4, if you take a measurement and your blood pressure is elevated, try taking it again after some time. Body position can also impact blood pressure so be sure that you are seated with your legs uncrossed, feet on the floor, with your arm supported so that your elbow is at heart level when taking measurements5.
4. How is blood pressure affected by pregnancy?
A range of things – from diet to water balance to exercise – can affect the force of blood on your arterial walls and, therefore, your blood pressure6. During pregnancy, your cardiovascular system changes dramatically – expanding plasma volume, increasing cardiac output, and increasing blood flow to and through the placenta.
Here are the key factors affecting blood pressure:
Here are the key factors affecting blood pressure:
- Blood volume: when fluid moves through a tube (like blood through your arteries), an increased amount of fluid puts more pressure against the arterial walls. During pregnancy, the volume of plasma in your blood increases by 6% in the first trimester, 18% in the second trimester, and 42% in the third trimester!7
- Cardiac output: the combination of heart rate and stroke volume (how much blood is pushed from the heart into the arteries with each beat). Anything that increases cardiac output, also increases blood pressure. During pregnancy, heart rate increases by 10-20 bpm up through the third trimester8. Stroke volume also increases nearly 1.5x across pregnancy.
- Peripheral resistance: how much resistance is the blood trying to flow against when it moves through your arteries. Resistance is impacted by viscosity (i.e. how “thick” your blood is), and by the constriction (tightening) or dilation (opening) of your blood vessels9. During pregnancy, specific hormones and other signaling molecules, as well as restructuring of blood vessels in the uterus and placenta act to decrease peripheral resistance and allow easier blood flow10.
In many pregnancies, the body makes adjustments to allow for cardiovascular changes that would normally raise blood pressure – blood flow, increases in blood volume, and the higher cardiac output – to add a counterbalance that keeps blood pressure in a healthy range. For example, decreasing peripheral resistance across pregnancy. However, in some pregnancies, those adjustments may not be sufficient or may go awry, resulting in high blood pressure, especially during the third trimester10.
5. Additional risk factors for high blood pressure
According to ACOG (as of 2022), there are certain risk factors for high blood pressure that are related to lifestyle and other risk factors that cannot be changed. These two categories are described as follows11:
What lifestyle habits can affect my blood pressure?
Lifestyle habits also can affect blood pressure. These are things you can change? You are at greater risk of high blood pressure if you
- Are overweight
- Are not physically active
- Smoke cigarettes
- Drink more than two alcoholic drinks per day
- Eat a poor diet (too much fat, not enough fruits and vegetables)
- Eat too much salt
Source: https://www.acog.org/en/womens-health/faqs/preeclampsia-and-high-blood-pressure-during-pregnancy
What are risk factors for high blood pressure that cannot be changed
The following factors that increase the risk of high blood pressure cannot be changed:
- Age-Blood pressure increases with age.
- Family history - High blood pressure tends to run in families.
- Medical conditions - Certain diseases, such as diabeted mellitus and kidney disease, increase the risk of high blood pressure
- History of preeclampsia
6. Ways to control blood pressure
Just like natural changes in pregnancy affect the key factors regulating blood pressure, ACOG recommends specific lifestyle changes to help control blood pressure:
Making lifestyle changes can decrease your risk of developing high blood pressure in the future
Lifestyle habits also can affect blood pressure. These are things you can change? You are at greater risk of high blood pressure if you
- Quit smoking.
- Lose weight if you are overweight.
- Limit your intake of alcohol.
- Exercise resgularly.
- Cut back on salt.
- Change your diet - The DASH (Dietary Approaches to Stop Hypertension) eating plan focuses on heart-healthy foods. To find out more about DASH, go to www.nhlbi.nih.gov/health/resources/heart/hbp-dash-index
- Relieve stress
Source: https://www.acog.org/en/womens-health/faqs/preeclampsia-and-high-blood-pressure-during-pregnancy
To expand, here is how some of these changes affect blood pressure:
Before
- Salt intake – Table salt and sodium in food affects both the volume of blood moving through your blood vessels and the ability of your blood vessels to dilate (expand). Greater blood volume and smaller space for blood flow = higher pressure on arterial walls 12.
- Exercise – increasing physical activity improves blood flow. Improved blood flow reduces blood pressure. A recent study suggests that all types of exercise (resistance training, aerobic exercise, and a combination of the two – are all effective at reducing resting blood pressure during pregnancy 13.
- Diet – “heart healthy” foods that lower cholesterol intake and decrease blood sugar and triglycerides positively impact blood flow, and, therefore, blood pressure. In addition, increasing potassium in your diet can counterbalance salt intake14. ACOG recommends the DASH eating plan – https://www.nhlbi.nih.gov/education/dash-eating-plan.
7. Why is high blood pressure important to track during pregnancy?
Elevated blood pressure puts strain on systems across your body and can lead to additional health issues like kidney failure, heart attack, heart failure, or stroke. High blood pressure can also lead to preterm birth and increases the likelihood of a cesarean birth15.
A serious high blood pressure disorder is called preeclampsia. Preeclampsia is when high blood pressure starts to affect other organs, like the kidneys or liver, and can happen during pregnancy or early in the postpartum period15.
A serious high blood pressure disorder is called preeclampsia. Preeclampsia is when high blood pressure starts to affect other organs, like the kidneys or liver, and can happen during pregnancy or early in the postpartum period15.
8. What are the warning signs of preeclampsia?
Preeclampsia can happen during pregnancy or in the early postpartum period and can develop without a patient even realizing it. For that reason, doctors recommend tracking blood pressure regularly and knowing the warning signs of preeclampsia 16. These include:
9. Why do I need to take my blood pressure at home?
Consistency is key when tracking changes in blood pressure. For many people, it is simply easier to get daily blood pressure measurements in the comfort and convenience of your own home. In addition, when patients have their blood pressure taken in a clinical setting, up to 30% of the measurements will reflect an inaccurately high blood pressure reading. This is called ‘White Coat Hypertension” and is likely related to being in a hospital environment. To rule this out, many doctors recommend getting blood pressure measurements in both a home and clinical setting so that they can compare measurements in each setting17.
10. How should I set myself up to get an accurate blood pressure measurement at home?
According to the American Heart Association18, to ensure that your are getting the most accurate blood pressure measurement, there are a few steps to take before and during the measurement:
Before
- Go pee! A full bladder can affect your blood pressure.
- Avoid blood pressure spiking activities in the 30 minutes before you take your blood pressure. This includes smoking, drinking caffeine, and exercising.
- Relax (if possible!). For five minutes before taking your blood pressure, try to sit and relax.
- Make sure you are seated in a comfortable, upright position with your feet flat on the floor and your back supported.
- Place the cuff on your bare upper arm about an inch (2-3 cm) above the elbow. If you need to roll up your sleeve, make sure the blood flow is not constricted.
- Tighten the cuff around your arm without making it too tight. You should be able to fit your finger between the cuff and your arm.
During
- Keep your arm still
- Try to avoid talking.
11. What affects blood pressure measurements?
Getting an accurate blood pressure measurement is key for tracking and treatment – an innaccurate low blood pressure measurement may give a false sense of security, an inaccurate high blood pressure measurement may spark unnecessary concern.
A few things can affect your blood pressure measurement, including: how you are sitting, what you’ve been doing, and how you are feeling before taking your blood pressure 19.
Before
- How you are sitting – Crossing your legs and hanging your arm down at your side can cause an elevated blood pressure measurement. To get a more accurate measurement, try keeping both feet flat on the floor with your arm resting on a table at chest height.
- What you have been doing – Exercising, eating, or drinking (especially something with caffeine!) within 30 min of taking your blood pressure can cause your measurement to be higher. To get an accurate blood pressure measurement, try taking measurements before or 30 min after you eat, exercise, or have your morning coffee.
- How you are feeling – simply being nervous can elevate your measurement. Try to relax as best you can before and while taking a measurement.
12. Why do I need to take my blood pressure every day / twice a day (or more)
Having consistency in your blood pressure measurements allows for you and your doctor to track trends and catch abnormal changes, such as sustained elevation in blood pressure (hypertension), sudden increases, or sudden drops.
Since blood pressure can change throughout the day, naturally and in response to the ins-and-outs of daily life, many doctors recommend two measurements each day: one early in the day and another towards the end of the day. Your doctor may have specific recommendations for you.
13. What happens if I miss a measurement or forget to take my blood pressure altogether?
With blood pressure tracking, consistency is key but it is never too late to get back into a rhythm. Life gets hectic and logging some measurements is better than logging zero measurements. If you are having a hard time remembering to take your blood pressure, adjust your text reminders from Bloomlife Connects. If you are having a hard time navigating how it fits into your day, find some inspiration in other user stories.
14. Why do I need to continue taking BP postpartum?
Consistently taking blood pressure measurements after baby’s birth for up to six weeks will help you and your doctor keep an eye on how your blood pressure is returning to pre-pregnancy levels20. In addition, it is important to continue looking for signs and symptoms of preeclampsia since postpartum preeclampsia accounts for nearly 6% of all preeclampsia cases21.
15. Bloomlife Connects Mom Stories
Early riser:
“My toddler wakes up at 6:30 every morning and goes to sleep at 7. Everything in the middle is crazy! I have been getting into a habit of waking up a little earlier so I can stretch a bit and have some quiet before the storm. That’s when I take my blood pressure. And then when she goes to sleep, I have my quiet back and try to get another measurement around 8pm.” – Ali, 31 weeks pregnant.
Watching a show before bed:
“I am supposed to get two measurements each day but the mornings have been a bit tricky. I know that I’ll miss a morning or two so I try to make sure I always get one later in the day. For me, it’s when I’m watching a show at night, around 9pm. I have my whole set up near my couch, with the remote next to the monitor so I don’t forget.” – Jess, 36 weeks pregnant.
At work:
“It took me a little while to find time that worked best in my day and I did miss a whole bunch of days when I started. I found that when I take my monitor to work, it's much easier to stick to a schedule: when I sit down at my desk and right before I leave at the end of the day. Done. So much easier!” – Laura, 29 weeks pregnant.
With the kids:
“My five year old loves to play doctor so she is the one who makes sure I take my blood pressure. It is the first thing she wants to do when she wakes up. And it is her favorite ‘after dinner activity’. She checks my cuff (I put it on), gives me a little thumbs up, and then pushes the Start button for me. It’s so cute. We have been having a lot of fun with it.” – Meghan, 17 weeks pregnant.
Finding time later in pregnancy
“I’m having twins and I feel HUGE right now. I need to stop and sit a lot of times during the day. I set up a ‘blood pressure station’ in my kitchen. Whenever I sit down to take a break, I take my blood pressure. I definitely get WAY more readings than I need but I always have at least two logged each day!” – Ariana, 34 weeks pregnant
“Me time” post baby:
“I had such a great routine when I was pregnant but, as you can probably expect, everything got thrown up in the air once I had my little guy. My husband has been super supportive though and we talked about how important it is for me to keep an eye on my blood pressure right now. So I get at least 15 minutes of ‘me time’ each morning and night. He takes the baby, sometimes on a walk, sometimes just into another room, and I get to relax and get a measurement. Taking my blood pressure has been such a great excuse for adding a little bit of quiet into my day!” – Nicole, 4 weeks postpartum
‘Sleep when the baby sleeps’ = take BP when the baby sleeps
“I definitely cannot ‘sleep when the babies sleep’ during the day so I’ve decided to flip it and ‘take my blood pressure when the babies sleep’. I get one or two magical windows in my day when they are both asleep (or at least one with the other in the swing!). It’s the only way it works in my day but it’s been working so far!” – Callie, 3 weeks postpartum