Lowering blood pressure during pregnancy involves a combination of dietary changes, physical activity, sleep positioning, and in some cases medication. The threshold for high blood pressure in pregnancy is 140/90 mm Hg or higher on two readings taken at least four hours apart, while readings of 160/110 or above are considered severe. What works depends on the type and severity of your hypertension, but several strategies are both safe and effective.
Types of High Blood Pressure in Pregnancy
Not all pregnancy-related blood pressure problems are the same, and knowing which type you’re dealing with shapes how it’s managed. Chronic hypertension means you had high blood pressure before getting pregnant or it was detected before 20 weeks. Gestational hypertension develops after 20 weeks in someone who previously had normal readings. Preeclampsia is a more serious condition that also develops after 20 weeks and involves high blood pressure along with protein in the urine or other organ problems. Women with chronic hypertension can also develop preeclampsia on top of their existing condition.
How Diet Affects Blood Pressure
The DASH diet (Dietary Approaches to Stop Hypertension) is one of the most studied dietary patterns for blood pressure, and it shows real benefits during pregnancy. In a randomized trial of 60 pregnant women with gestational or chronic hypertension, those following the DASH diet had significantly lower systolic and diastolic blood pressure after one and two months compared to a control group. A larger observational study of over 3,400 women found that higher DASH diet adherence was associated with lower diastolic blood pressure at mid-pregnancy.
The core of the DASH diet is straightforward: 4 to 5 servings each of fruits and vegetables daily, 6 to 8 servings of whole grains, 2 to 3 servings of low-fat dairy, lean protein in moderate amounts, and nuts, seeds, or legumes several times a week. Sweets and saturated fats stay limited.
Sodium deserves special attention. While the American College of Obstetricians and Gynecologists does not recommend strict salt restriction specifically to prevent preeclampsia, higher sodium intake is clearly linked to worse outcomes. Women consuming a median of 3.7 grams of sodium per day had a 54% higher risk of gestational hypertension and a 20% higher risk of preeclampsia compared to those eating around 2.6 grams daily. Keeping sodium moderate, around 2,300 mg per day or less, is a reasonable target.
Exercise During Pregnancy
Physical activity is one of the most reliable ways to keep blood pressure in check, and it’s safe for most pregnancies. Federal guidelines recommend at least 150 minutes of moderate-intensity aerobic activity per week, spread across multiple days. Walking, swimming, stationary cycling, and prenatal yoga all count. A systematic review found that regular aerobic exercise during pregnancy was linked to a significantly lower incidence of hypertensive disorders, along with lower rates of gestational diabetes and cesarean delivery.
If you were already active before pregnancy, you can generally continue at your previous intensity. Activities to avoid include contact sports with a risk of abdominal trauma, anything with a high fall risk, and scuba diving, which poses unique risks to fetal circulation.
Sleep Position Matters
How you sleep has a measurable effect on your cardiovascular system during pregnancy, particularly in the second and third trimesters. Lying on your back compresses the large vein (the inferior vena cava) that returns blood to your heart. This reduces cardiac output by about 16% and cuts blood flow to the uterus by nearly 24% compared to lying on your side.
Side sleeping, whether left or right, produces similar cardiovascular benefits. Both positions avoid the vena cava compression that happens when you’re on your back. Research shows that heart rate is about 5 beats per minute lower and systolic blood pressure roughly 3 mm Hg lower in a lateral position compared to the positions that follow a change from side-lying. For the later months of pregnancy, making a habit of sleeping on your side is a simple way to support healthy blood flow.
Calcium Supplementation
If your dietary calcium intake is low, supplementation can meaningfully reduce your risk of preeclampsia. The World Health Organization recommends 1.5 to 2 grams of calcium per day for pregnant women in populations where calcium intake tends to be low, noting this can cut preeclampsia risk by at least 50%. Ongoing research suggests that even 500 mg per day may offer protection, though the higher dose has stronger evidence behind it. Most prenatal vitamins contain only a fraction of this amount, so a separate calcium supplement is typically needed to reach these levels.
Low-Dose Aspirin for High-Risk Women
If you have risk factors for preeclampsia, such as a history of preeclampsia in a prior pregnancy, chronic hypertension, kidney disease, or carrying multiples, low-dose aspirin (81 mg per day) is recommended as a preventive measure. The U.S. Preventive Services Task Force and the American College of Obstetricians and Gynecologists both endorse starting it after 12 weeks of gestation, ideally before 16 weeks, and continuing daily until delivery. This is specifically for women identified as high risk, not a blanket recommendation for all pregnancies.
Medications That Are Safe and Unsafe
When lifestyle changes aren’t enough, several blood pressure medications have long safety records in pregnancy. The most commonly used options work by relaxing blood vessels or reducing the signals that cause them to constrict. Your provider will choose based on your specific situation, how far along you are, and how your blood pressure responds.
What’s critically important is knowing which medications to avoid. ACE inhibitors and ARBs, two of the most commonly prescribed blood pressure drugs outside of pregnancy, should not be used after the first trimester. They can cause dangerously low levels of amniotic fluid, which leads to poor lung development, kidney problems, skull bone defects, growth restriction, and in severe cases, fetal death. If you were taking one of these medications before becoming pregnant, your provider will switch you to a pregnancy-safe alternative.
Monitoring Blood Pressure at Home
Home monitoring gives you and your provider a clearer picture of your blood pressure patterns than occasional office visits alone. Use an automatic, cuff-style monitor that wraps around your upper arm. Wrist and finger monitors are less reliable. Make sure the cuff fits your arm, as an incorrect size will give inaccurate readings.
Each time you measure, sit with your feet flat on the floor and your arm supported at heart level on a flat surface. A pillow under your arm can help with positioning. Don’t talk or use your phone during the reading. Take two measurements one minute apart and record both. Measuring at the same time each day creates the most useful data for tracking trends.
Warning Signs That Need Immediate Attention
Some symptoms signal that blood pressure has reached a dangerous level or that preeclampsia is developing. A severe headache that doesn’t respond to rest or typical remedies, visual changes like blurred vision or seeing spots, and pain in the upper abdomen (particularly under the ribs on the right side) all warrant urgent evaluation. Sudden swelling in the face and hands, nausea or vomiting that appears after the first trimester, and a blood pressure reading of 160/110 or higher at home are also reasons to seek care immediately rather than waiting for your next appointment.