Preeclampsia can’t always be prevented, but several proven strategies significantly lower your risk. The most effective single intervention is low-dose aspirin, recommended for anyone with identified risk factors. Beyond that, a combination of diet, exercise, weight management, calcium intake, and early screening gives you the best chance of avoiding this dangerous pregnancy complication.
Why Preeclampsia Happens
Understanding the underlying biology helps explain why certain interventions work. During a healthy pregnancy, blood vessels in the uterus remodel to deliver a rich blood supply to the placenta. In preeclampsia, this remodeling fails. The placenta doesn’t get enough blood flow, becomes oxygen-starved, and starts releasing substances into the mother’s bloodstream that damage blood vessel linings throughout the body. That widespread blood vessel dysfunction is what drives the hallmark symptoms: high blood pressure, protein in the urine, and organ stress.
Because the root problem starts in the placenta during the first trimester, the most effective preventive steps begin early in pregnancy, ideally before 16 weeks.
Know Your Risk Level
The U.S. Preventive Services Task Force divides preeclampsia risk into two tiers, and your category determines whether you should start aspirin therapy.
High-risk factors (one is enough to qualify for aspirin):
- History of preeclampsia in a previous pregnancy
- Carrying multiples (twins, triplets)
- Chronic high blood pressure
- Type 1 or type 2 diabetes diagnosed before pregnancy
- Kidney disease
- Autoimmune conditions like lupus or antiphospholipid syndrome
Moderate-risk factors (two or more together qualify for aspirin):
- First pregnancy
- Pre-pregnancy BMI over 30
- Family history of preeclampsia (mother or sister)
- Age 35 or older
- More than 10 years since your last pregnancy
- IVF conception
- Previous low-birth-weight baby or adverse pregnancy outcome
- Lower income
Black women face elevated risk due to longstanding inequities in healthcare access, environmental exposures, and resource distribution. This is a social and systemic pattern, not a biological one.
Low-Dose Aspirin
Daily low-dose aspirin (81 mg) is the single most well-supported preventive measure. ACOG recommends starting it between 12 and 28 weeks of gestation, with the best results when you begin before 16 weeks. You continue taking it daily until delivery. This isn’t something to start on your own; your prenatal provider will assess your risk factors and prescribe it if appropriate.
Aspirin works by reducing inflammation and improving blood flow to the placenta during the critical window when those uterine blood vessels are still remodeling. Starting later in pregnancy is less effective because much of the placental development has already occurred.
Diet: The Mediterranean Pattern
Among dietary approaches, a Mediterranean-style eating pattern has the strongest evidence for lowering preeclampsia risk. This means emphasizing fruits, vegetables, whole grains, legumes, nuts, olive oil, and fish while limiting processed foods, red meat, and added sugars.
Observational studies consistently show protective effects ranging from 22% to 69% risk reduction depending on how closely women followed the pattern. In one large study, women in the highest quartile of Mediterranean diet adherence had a 42% lower risk of developing hypertensive disorders of pregnancy compared to those in the lowest quartile. Another found that women with low adherence had 3.8 times higher odds of developing preeclampsia. Early adherence matters: women who scored highest on a Mediterranean diet assessment at 8 to 13 weeks of gestation had a 69% lower risk of preeclampsia compared to those who scored lowest.
Clinical trials have been somewhat less dramatic than the observational data, with some showing trends toward reduced preeclampsia that didn’t reach statistical significance. One trial, however, found that women receiving structured Mediterranean diet guidance had significantly lower rates of hypertension and preeclampsia (18.2% vs. 32.5%) compared to those receiving standard dietary advice. The overall picture favors this eating pattern, even if it’s not a guarantee.
Calcium Supplementation
If your diet is low in calcium, supplementation can meaningfully reduce your preeclampsia risk. The World Health Organization recommends 1.5 to 2 grams of elemental calcium daily for pregnant women in populations with low dietary calcium intake. This is particularly relevant if you don’t regularly consume dairy, fortified foods, or other calcium-rich sources. In populations where calcium intake is already adequate, supplementation offers less benefit.
Exercise During Pregnancy
Regular physical activity during pregnancy is linked to a lower incidence of gestational hypertensive disorders, including preeclampsia. ACOG and the U.S. Department of Health and Human Services recommend at least 150 minutes of moderate-intensity aerobic activity per week, spread across multiple days rather than packed into one or two sessions. Walking, swimming, stationary cycling, and prenatal yoga all count. The goal is consistent moderate effort, not high intensity.
Weight Gain Targets
Gaining too much weight during pregnancy increases your risk of preeclampsia, and the recommended range depends on your pre-pregnancy BMI. The Institute of Medicine guidelines suggest:
- Underweight (BMI under 18.5): 12.5 to 18 kg (about 28 to 40 lbs)
- Normal weight (BMI 18.5 to 24.9): 11.5 to 16 kg (about 25 to 35 lbs)
- Overweight (BMI 25 to 29.9): 7 to 11.5 kg (about 15 to 25 lbs)
- Obese (BMI 30 or higher): 5 to 9 kg (about 11 to 20 lbs)
Staying within these ranges doesn’t eliminate risk, but exceeding them is consistently associated with worse outcomes. If you enter pregnancy at a higher BMI, the smaller recommended gain reflects the fact that your body already has sufficient energy reserves to support fetal growth.
Sleep and Breathing
Sleep-disordered breathing, particularly obstructive sleep apnea, is an underrecognized risk factor. Pregnant women at high risk for sleep apnea have roughly 2.7 times the odds of developing preeclampsia compared to those at low risk. Symptoms to watch for include loud snoring, gasping or choking during sleep, excessive daytime sleepiness, and morning headaches. If your partner notices you stop breathing briefly during sleep, bring it up at your next prenatal visit. Sleep apnea risk is closely tied to pre-pregnancy BMI and perceived stress levels.
Blood Tests That Predict Risk
Newer blood tests can help identify preeclampsia before symptoms appear. These measure the ratio between two placenta-related proteins circulating in your blood. A ratio below 38 effectively rules out preeclampsia developing within the next week, with a negative predictive value above 96%. A ratio at or above 38 signals the need for closer monitoring. Higher ratios indicate more immediate concern, with very elevated levels associated with the need for delivery within 48 hours.
These tests are increasingly available in clinical practice, particularly in Europe and parts of the U.S. They’re most useful when your provider suspects preeclampsia but wants to confirm or rule it out before escalating care. They aren’t yet part of routine screening for all pregnancies, but they add a powerful tool for women already flagged as higher risk.
Putting It All Together
No single intervention eliminates preeclampsia risk entirely. The strongest approach combines multiple strategies: take aspirin if your risk profile qualifies, eat a diet rich in vegetables, fruits, whole grains, and healthy fats, get 150 minutes of moderate exercise weekly, stay within your recommended weight gain range, and supplement calcium if your intake is low. Start as early in pregnancy as possible. The placental changes that set the stage for preeclampsia begin in the first trimester, so the interventions with the biggest impact are the ones you adopt before 16 weeks.