5 tips to avoid preeclampsia blood pressure ranges

Preeclampsia is a serious and complex condition that can lead to severe pregnancy complications. In my previous two blogs, I discussed blood tests to help predict the risk of preeclampsia and risk factors to address before conception.

In this blog, you’ll learn about preeclampsia blood pressure ranges and how preeclampsia differs from hypertension during pregnancy (gestational hypertension).

We’ll also cover science-backed strategies to reduce the risks of preeclampsia during pregnancy.

Preeclampsia blood pressure ranges

The American College of Obstetrics and Gynecology (ACOG) recently updated their cutoffs for blood pressure ranges in pregnancy, in step with the revised American College of Cardiology/American Heart Association guidelines of 2017.

The updated ACOG cutoffs are:

Normal: Less than 120/80 mm 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

However, ACOG still defines gestational hypertension as new-onset high blood pressure occurring after the 20th week of gestation, with a systolic blood pressure of at least 140 and/or diastolic blood pressure of at least 90 in at least two blood pressure readings taken at least four hours apart (1).

So, how is preeclampsia defined?

“Preeclampsia occurs when blood pressure exceeds 140/90 mm Hg after 20 weeks of gestation” (2).

“It is accompanied by proteinuria, or signs/symptoms like right upper quadrant pain, persistent epigastric pain, severe headache, blurry vision, thrombocytopenia, elevated liver enzymes, renal insufficiency and pulmonary edema. Uteroplacental ischemia in preeclampsia results in fetal growth restriction and oligohydramnios. Maternal consequences of the condition include placental abruption and increased risk of preterm delivery” (2).

Be aware that circadian rhythms influence blood pressure; thus, readings may fluctuate throughout the day.

Additionally, preeclampsia blood pressure ranges may be changing in the near future—there is a call to redefine criteria for hypertensive disorders of pregnancy to match the cutoff of 130/80 instead of 140/90 (2).

Thankfully, several therapeutic interventions have been shown to reduce the risks of preeclampsia during pregnancy.

Tip #1: Take aspirin as recommended by your medical team if you are at risk of preeclampsia.

Aspirin is currently the only medication recommended to prevent preeclampsia (3).

Aspirin for preeclampsia has been studied since 1979, with doses ranging from 50 to 150 mg daily. Currently, the general recommendation from ACOG is that women at high risk of developing preeclampsia begin aspirin at weeks 12 to 28 of pregnancy and continue until delivery (3).

A large meta-analysis of 16 trials totaling 18,907 pregnancies found that women who took aspirin were 38% less likely to develop preterm preeclampsia, preeclampsia that occurs before 37 weeks of pregnancy (relative risk, 0.62; 95% confidence interval, 0.45–0.87) (4).

Early intervention with aspirin was critical for preterm preeclampsia prevention; aspirin initiated <16 weeks gestation at a dose >100mg was associated with an even greater reduction risk—67% reduction—in preterm preeclampsia (relative risk, 0.33; 95% confidence interval, 0.19-0.57) (4).

In this meta-analysis, prophylactic aspirin did not have a notable effect on preventing term preeclampsia (preeclampsia after 37 weeks gestation) (relative risk, 0.92; 95% CI: 0.70-1.21) (4).

Does that mean taking aspirin later in pregnancy will not benefit term preeclampsia symptoms? Not necessarily. Aspirin may be beneficial for women with late-onset preeclampsia, but the effects are less noticeable.

As the study authors note, “There are two possibilities for the apparent effect of aspirin in the reduction of the risk of preterm preeclampsia, but not term preeclampsia.

First, the pathophysiologic effect of the two conditions is different, and aspirin affects only the cases of preterm preeclampsia. Second, aspirin reduces the risk of both preterm preeclampsia and term preeclampsia, and its effect is to shift the gestational age at delivery with preeclampsia to the right so that the cases of term preeclampsia that are prevented are replaced by cases of preterm preeclampsia (4).”

The authors also suggest that the current dose recommended by professional bodies be increased from 75-80 mg/day to the onset of treatment at ≤16 weeks of gestation at ≥100 mg/day (4).

Discuss with your medical team whether aspirin is a good match for you based on your risk factors and health history, and follow the dosing recommendations you receive.

Preeclampsia blood pressure ranges

It might seem discomforting to take a pharmaceutical, but aspirin has been extensively researched and has been used for decades. It works and is a small daily step that can greatly reduce your risk of preeclampsia.

While there may be herbal alternatives to aspirin, none has been tested for safety and efficacy the way aspirin has.

It only makes sense to discuss alternatives to aspirin with your healthcare team when you have an allergy or specific condition that would contraindicate aspirin use.

Read on to learn what you can do in addition to aspirin to reduce your risk.

Tip #2: Supporting healthy nutrient levels might benefit preeclampsia blood pressure ranges. But the research is very mixed.

Those at risk of preeclampsia might have increased needs for electrolytes, omega-3 fatty acids, antioxidants, calcium, & magnesium. Emphasis on might.

Pregnant women with preeclampsia may have reduced serum sodium and potassium levels compared to those with normal blood pressure (5).

In a small study of 30 pregnant individuals with preeclampsia and 30 pregnant individuals with normal blood pressure, the researchers found that women with preeclampsia had significantly reduced serum sodium, with an average of 136.13 mmol/L (SD = 4.17 mmol/L), vs. normotensive women with an average of 142.17 mmol/L (SD = 5.66 mmol/L).

Serum potassium was significantly reduced in those with preeclampsia compared to those without, with an average of 3.45 mmol/L (SD = 0.54) and 3.98 mmol/L (SD = 0.36 mmol/L), respectively (5).

Other studies on sodium and potassium levels have yielded significant but conflicting results, with aberrations in sodium and potassium all over the map.

While this is confusing, a good takeaway is to pay attention to the electrolyte panel, interpreting the results based on ranges for the trimester of pregnancy when the blood sample is taken.

Additionally, those with preeclampsia may have lower levels of omega-3 fatty acids.

Research has shown altered long-chain polyunsaturated fatty acids in preeclampsia patients (6, 7).

Wadhawi et al. found that women with preeclampsia had lower levels of DHA in the maternal plasma, cord, and placental between the 16th and 20th week of gestation (6).

Another study found that women with preeclampsia had significantly lower levels of DHA and omega-3 fatty acids (p<0.001) and higher levels of omega-6 and arachidonic acid (p<0.05) than those with normal blood pressure (7).

Can omega-3 supplementation benefit preeclampsia blood pressure ranges?

A 2019 animal study found that supplementation with omega-3 and vitamin E was beneficial in late-onset preeclampsia and normalized the levels of angiogenic and transcription factors (8). However, there was no benefit for early-onset preeclampsia. The authors concluded that these results suggest supplementing with omega-3 and vitamin D may lessen the severity of early-onset preeclampsia (8).

Despite the promising results of this study, human studies have provided mixed results.

A 2018 Cochrane review of 20 trials concluded that preeclampsia may be reduced by omega-3 supplementation (RR 0.84, 95% CI, 0.69 to 1.01) but noted the quality of evidence is poor. For gestational hypertension, there was no difference in the risk of developing high blood pressure for those who supplemented with omega-3 versus those who did not (RR 1.03, 95% CI, 0.89 to 1.20) (10).

Vitamins C & E should be considered for those at risk of preeclampsia.

A prospective study of 57,346 pregnancies found an association between dietary vitamin C during weeks 21-25 of gestation and risk of preeclampsia, severe preeclampsia, and HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome (9).

Specifically, the researchers found a trend toward decreasing preeclampsia with increasing dietary vitamin C.

For those with a dietary intake below 70 mg/day, the odds of preeclampsia was 1.21 (95% confidence interval 0.83 to 1.75). A dietary intake greater than 275 mg/day resulted in lower odds of preeclampsia (95% confidence interval 0.40 to 1.23). However, these findings were statistically non-significant, and the confidence interval indicates there may be no association between less dietary vitamin C and preeclampsia (9).

It is worth noting that this study relied on a food frequency questionnaire to track vitamin C intake, meaning the participants had to recall their diet for four weeks before filling out the questionnaire. Although this is a common way to gather information, there is potential for subjective bias and recall error.

The levels of vitamin C required to lower preeclampsia risk are obtainable via a nutrient-dense diet and a high-quality prenatal multi-nutrient matched to the individual patient.

Studies that looked explicitly at vitamin supplementation provided more insight but, again, with mixed results.

A randomized placebo control trial found that supplementing with 1000 mg of vitamin C & 400 IU of vitamin E between 16-22 weeks gestation resulted in a significant reduction in preeclampsia (OR: 0.24 (0.08-0.70, p=0.002) and a 21% decrease in PAI-1/PAI-2 ratio (95% CI 4-35, p=0.015). Preeclampsia occurred in 17% of women in the placebo group and 8% in the vitamin group (adjusted OR:0.39 [0.17-0.90], p=0.02) (11).

In contrast, other studies found no reduction in preeclampsia risk with the same dose of vitamins C & E supplementation (12, 13).

Despite the mixed evidence, supplementation with vitamins C and E may be beneficial in preventing preeclampsia for those at increased risk.

However, vitamin E supplementation alone is a different story. A 2009 study of 57,346 pregnancies found that the odds of all forms of preeclampsia increased with vitamin E intake exceeding 18mg/day (9). Thus, more is not necessarily better. It’s a matter of the right amount for the person during that moment in time, especially concerning powerful antioxidants such as vitamin E.

Selenium, another antioxidant that plays a role in cellular repair and survival (14), may also contribute to preeclampsia prevention (15, 16).

A 2015 meta-analysis of thirteen observational studies found an inverse association between blood selenium level and risk of preeclampsia. The same analysis looked at three randomized control trials and found that selenium supplementation significantly reduced the incidence of preeclampsia (relative risk 0.28, 0.09 to 0.84, p=0.02) (15).

The dose and timing varied between the observed RCTs, so more clinical trials are needed to determine the best dose and duration for selenium supplementation to prevent preeclampsia.

Frustratingly, however, a study of 69,792 pregnant women in a Norwegian cohort found no significant associations between selenium status or selenium supplementation and preeclampsia risk (17).

A 2022 review on nutritional factors that affect the risk of preeclampsia did not indicate any risk reduction from vitamins C & E but does recommend consuming optimal amounts of fruits, vegetables, dietary fiber, and selenium to reduce preeclampsia risk (16). Polyphenols and antioxidants in plant foods possess profound anti-inflammatory benefits, and eating the rainbow truly makes a difference.

For example, punicalagin, a polyphenol found in pomegranate juice, has been shown to reduce oxidative stress, restore angiogenic balance, and improve blood pressure in an animal model of gestational hypertension (18).

In contrast, Western dietary patterns (also referred to as a Standard American Diet) appear to worsen preeclampsia outcomes drastically. Abbasi et al. (2021) observed a nearly six-fold increase in the odds of preeclampsia for women who consumed a Western-type diet, characterized by a higher intake of processed meat, red meat, refined grains, sweets, and fried potatoes, and lacking in legumes and colorful vegetables (19).

Western-type diets often lack optimal, or even adequate, dietary fiber. The authors of the 2022 review mentioned above observed that adequate dietary fiber (25-30 grams/day) is protective against preeclampsia* (20).

Calcium and magnesium levels may be lower in those with preeclampsia and gestational hypertension (21).

“A probable theory to this observation may be that when serum calcium levels decreased, the levels of intracellular calcium increased, leading to constriction of smooth muscles in blood vessels and therefore increased vascular resistance [20]-[22], culminating in a raised systolic and diastolic blood pressure. Furthermore, previous reports suggest that altered calcium homeostasis, as exhibited by increased calcium excretion, is associated with higher blood pressure levels” (21).

The same authors go on to state that reduced calcium paired with reduced magnesium and the needed interplay of these two minerals to maintain balanced vasoconstriction and blood pressure contribute to hypertensive disorders in pregnancy.

A 2018 Cochrane review on calcium for preeclampsia prevention looked at low-dose (<1 gram/day) and high-dose (>1 gram/day) calcium to prevent preeclampsia. The authors concluded that high-dose supplementation with calcium may reduce the risk of preeclampsia, particularly for women consuming low dietary calcium. However, calcium supplementation resulted in a small but increased risk of HELLP syndrome (22).

Another study combined calcium with aspirin for pregnant women with chronic hypertension and an abnormal uterine artery Doppler (23).

The women took 2 grams of calcium and 100 mg aspirin daily beginning at weeks 20-27 of pregnancy or a placebo. The results showed that calcium plus aspirin decreased superimposed preeclampsia and fetal growth restriction, although the risk reduction was not statistically significant. Superimposed preeclampsia occurred in 52.2% of the calcium plus aspirin group and 71.3% of the placebo group (p=0.112) (23).

A 2022 meta-analysis examining magnesium supplementation alone for preventing preeclampsia found that magnesium may be most beneficial for high-risk women. In studies only looking at healthy pregnant women, there was no significant risk reduction (RR: 0.91, 95% CI: 0.67 to 1.25, P = 0.57); however, studies that included both healthy pregnancies and high-risk pregnancies showed a significant reduction in the risk of preeclampsia (RR: 0.54, 95% CI: 0.35 to 0.83, P = 0.005; P for subgroup difference = 0.04) (24).

The takeaway? Supporting optimal nutrient intake based on general pregnancy needs and the patient’s unique health is likely the best approach to avoid preeclampsia blood pressure ranges.

Ideally, this means that the patient will receive professional and individualized guidance on nutrition and supplementation whenever possible.

And remember, when taking any vitamin or nutrient at a dose higher than you get from food or your prenatal multi-nutrient, consult your health care team. Contraindications and interactions may affect what dosage is safe for you based on your health conditions, family history, and medications.

Tip #3: Physical activity during pregnancy may reduce the risk of preeclampsia.

Spracklen et al. (2017) observed that regular physical activity, even light activity, such as a non-sedentary job that requires some movement, lowered preeclampsia risk.

Compared to women reporting 0-4.2 hours of activity a day, women who were active for an average of 8.25 hours per day had a significantly lower preeclampsia risk (adjusted OR 0.58, 95% CI 0.36, 0.95) (25).

In contrast, regularly performing heavy household chores or working more than 40 hours/week increased the risk of developing gestational hypertension and preeclampsia,

“In conclusion, we found that women with higher levels of PA [physical activity] during pregnancy tended to have a lower risk of preeclampsia, while women with increased levels of sedentary activity were at increased risk. As one of the few potentially modifiable factors associated with a reduced risk of preeclampsia, promotion of PA during pregnancy may be a promising approach for reducing the risk of the disease” (25).

Increasing movement may be as simple as taking a brisk daily walk and signing up for a prenatal exercise class. It’s important to receive individualized guidance on appropriate activities at different stages of pregnancy if you’re someone with health conditions that make exercise more challenging.

The benefits of exercise for blood pressure vary depending on whether the pregnant individual has healthy or high blood pressure. A meta-analysis of 18 RCTs observed that women susceptible to hypertension will see a more remarkable improvement in blood pressure and vascular health than those with normal blood pressure (26).

Tip #4 Mindfulness training may be an additional strategy to prevent preeclampsia.

Mindfulness is becoming increasingly understood as a safe and effective way to regulate the nervous system and may improve myocardial and endothelial function (27).

In a 2023 randomized control trial, pregnant women (</= 20 weeks gestation) with a history of a hypertensive disorder were randomized to receive eight weeks of phone-based mindfulness training or standard care (28).

Mindfulness training included a weekly 30-minute session focused on mindfulness-based stress reduction techniques. Additionally, participants were asked to practice 15 minutes of mindfulness daily by doing a body scan and breathing awareness meditations.

Standard care consisted of medications to treat hypertension, low-dose aspirin, and weekly check-ins.

The women in the mindfulness group had lower levels of hypertensive disorders of pregnancy than those who received standard care (9% vs. 29%; OR: 0.25, 95% CI, 0.02-2.65). However, because the confidence interval crosses 1, indicating no effect, these results were insignificant.

Despite this, systolic and diastolic blood pressure were significantly lower at the follow-up for those in the mindfulness group compared to the standard care group (28).

Tip #5: Work with a professional who can provide individualized testing and guidance

Patients with an elevated risk of preeclampsia or who develop preeclampsia during pregnancy should, whenever possible, seek out and receive individualized support from a professional or team of professionals who can help them identify modifiable nutrition and lifestyle factors.

It can be very overwhelming to go through all the information alone during pregnancy while also managing the emotions that can accompany the knowledge that you have a higher risk of a potentially serious pregnancy complication.

In my nutritional therapy practice, I provide not only individualized feedback, research, lab test interpretation, and insights but also share a lot of reassurance in the context of an emotionally intelligent approach.

Schedule a free 15-minute consultation call if you need preconception or pregnancy support for preeclampsia.

Are you a clinician looking to improve your resources for preeclampsia patients? Check out my self-paced masterclass, “What You Never Learned About Blood Work in Preconception, Pregnancy, & Postpartum.“

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