Research shows that pregnant women with the lowest folate levels face 2.35 times higher odds of developing high blood pressure during pregnancy compared to those with adequate folate. According to Gram Research analysis of 722 women, those with both uterine fibroids and low folate had 1.84 times greater risk than women without fibroids and adequate folate, suggesting that maintaining sufficient folate may be particularly important for pregnant women with fibroids.
Researchers studied 722 pregnant women to understand why those with uterine fibroids (noncancerous growths in the uterus) are more likely to develop high blood pressure during pregnancy. According to Gram Research analysis, women with the lowest folate levels were more than twice as likely to develop pregnancy-related high blood pressure compared to those with adequate folate. The study also found that women who had both fibroids and low folate faced even higher risks. While the research suggests folate may play an important role, scientists note that blood samples were collected after pregnancy, so they cannot yet prove that low folate causes the problem.
Key Statistics
A cross-sectional analysis of 722 pregnant women from the Boston Birth Cohort found that women in the lowest folate quartile had 2.35 times higher odds of developing high blood pressure during pregnancy compared to those in the highest folate quartile.
Among 722 pregnant women studied, those with both uterine fibroids and low folate had 1.84 times greater odds of hypertensive disorders of pregnancy compared to women without fibroids and adequate folate levels.
In a 2026 analysis of 722 pregnant women, the highest homocysteine levels (which increase when folate is low) were associated with 2.36 times higher odds of high blood pressure during pregnancy compared to the lowest homocysteine levels.
Among 722 participants in the Boston Birth Cohort, 12% had uterine fibroids and 10% developed high blood pressure during pregnancy, with nutrient deficiencies appearing to increase risk for both conditions.
The Quick Take
- What they studied: Whether vitamin and nutrient levels in pregnant women’s blood could explain why women with uterine fibroids are more likely to develop high blood pressure during pregnancy.
- Who participated: 722 pregnant women from the Boston Birth Cohort, a diverse group of women followed from pregnancy through their baby’s birth. About 12% had uterine fibroids, and 10% developed high blood pressure during pregnancy.
- Key finding: Women with the lowest folate (a B vitamin) levels were 2.35 times more likely to develop pregnancy-related high blood pressure. Women who had both fibroids and low folate faced even higher risks, with 1.84 times greater odds of high blood pressure.
- What it means for you: If you’re pregnant or planning pregnancy and have fibroids, maintaining adequate folate levels through diet or supplements may be important for reducing high blood pressure risk. However, this study cannot prove folate prevents the problem, only that low folate and fibroids appear together with higher risk. Talk to your doctor about your individual situation.
The Research Details
This study looked at information already collected from 722 pregnant women in the Boston Birth Cohort, a long-term research project tracking women’s health. Researchers examined blood samples taken after pregnancy to measure folate, vitamin B12, and vitamin D levels. They compared these nutrient levels between women who had uterine fibroids and those who didn’t, and between women who developed high blood pressure during pregnancy and those who didn’t.
The researchers used statistical methods to calculate the odds of developing high blood pressure based on nutrient levels. They looked at nutrients both as continuous measurements and by dividing women into four groups based on their nutrient levels (called quartiles). They also examined whether having both fibroids and low nutrients together created a greater risk than either factor alone.
This research approach is important because it examines real-world data from a diverse group of women, making the findings more applicable to different populations. By looking at multiple nutrients and their combinations, the study provides a more complete picture of how nutrition might affect pregnancy complications. Understanding these connections could help doctors identify which pregnant women with fibroids need extra monitoring or nutritional support.
The study’s main strength is its diverse participant group and complete data collection. However, the biggest limitation is that blood samples were collected after pregnancy ended, so researchers cannot determine whether low folate caused the high blood pressure or developed because of it. The study is also relatively small for this type of analysis, which means some findings may have occurred by chance. The cross-sectional design means researchers captured only a snapshot in time rather than following women throughout pregnancy.
What the Results Show
Among the 722 women studied, 87 had uterine fibroids (12%) and 72 developed high blood pressure during pregnancy (10%). Nutrient levels measured in blood samples did not differ between women with and without fibroids, suggesting the fibroids themselves don’t directly change how the body processes these vitamins.
However, folate levels showed a clear connection to high blood pressure risk. Women in the lowest folate group were 2.35 times more likely to develop high blood pressure compared to women in the highest folate group. This pattern held true even when researchers adjusted for other factors that affect blood pressure.
Homocysteine, a substance that increases when folate levels are low, also showed a strong connection to high blood pressure. Women with the highest homocysteine levels were 2.36 times more likely to develop high blood pressure than those with the lowest levels. Vitamin B12 and vitamin D did not show significant associations with high blood pressure risk.
When researchers examined the combined effect of having both fibroids and low folate, the risk increased further. Women with this combination had 1.84 times higher odds of developing high blood pressure compared to women without fibroids who had adequate folate. This suggests that fibroids and low folate may work together to increase risk, though the study found no statistical evidence that one factor amplified the other’s effect.
Previous research has shown that women with uterine fibroids have higher rates of high blood pressure during pregnancy, but the reasons remain unclear. This study adds to that knowledge by suggesting that nutritional status, particularly folate, may be part of the explanation. The findings align with broader research showing folate’s importance in pregnancy health and blood pressure regulation. However, most previous studies examined folate’s effects in general populations, not specifically in women with fibroids.
The most significant limitation is the timing of blood collection. Samples were taken after pregnancy ended, so researchers cannot determine whether low folate preceded high blood pressure or resulted from it. The study also cannot prove that low folate causes high blood pressure, only that they appear together. The sample size, while reasonable, was relatively small for examining multiple nutrient interactions. Additionally, the study relied on data collected for other purposes, which may have missed important information about folate intake through diet or supplements.
The Bottom Line
Pregnant women, especially those with uterine fibroids, should ensure adequate folate intake through diet (leafy greens, legumes, fortified grains) or prenatal vitamins containing folic acid. Current prenatal vitamins typically contain sufficient folate, but discuss your individual needs with your healthcare provider. This recommendation is based on moderate evidence from observational research and should complement, not replace, standard prenatal care and blood pressure monitoring.
This research is most relevant to pregnant women with diagnosed uterine fibroids and their healthcare providers. Women planning pregnancy who have fibroids should discuss folate status with their doctors. The findings may also interest women with high blood pressure risk factors during pregnancy. However, the study does not provide enough evidence to recommend routine folate supplementation beyond standard prenatal vitamins for all pregnant women.
Folate works throughout pregnancy to support healthy blood vessel function and reduce inflammation. If folate deficiency is contributing to high blood pressure risk, adequate levels should be maintained from early pregnancy onward. Benefits would not appear as a sudden change but rather as part of overall pregnancy health management. Prospective studies following women from early pregnancy are needed to determine realistic timelines for folate’s protective effects.
Frequently Asked Questions
Does low folate cause high blood pressure in pregnancy?
Research shows strong associations between low folate and pregnancy high blood pressure, but this study cannot prove causation since blood samples were collected after pregnancy. Prospective studies following women from early pregnancy are needed to confirm whether low folate directly causes the condition.
Should pregnant women with fibroids take extra folate supplements?
Standard prenatal vitamins contain adequate folate for most pregnancies. However, women with fibroids should discuss their individual folate needs with their healthcare provider, who can assess risk factors and recommend appropriate supplementation based on blood work and medical history.
What foods are high in folate for pregnant women?
Excellent folate sources include leafy greens (spinach, kale), legumes (lentils, chickpeas), asparagus, broccoli, avocado, and fortified grains. Prenatal vitamins also contain folic acid, the synthetic form of folate. Aim for variety across these food groups daily.
Can uterine fibroids cause high blood pressure during pregnancy?
Women with fibroids have higher rates of pregnancy high blood pressure, but the exact mechanism isn’t fully understood. This study suggests nutritional factors like folate may partially explain the connection, though fibroids themselves may also play a direct role.
How early in pregnancy should folate levels be adequate?
Folate is critical from conception through the first trimester for fetal development. Women planning pregnancy should ensure adequate folate intake before conception. Once pregnant, maintaining adequate folate throughout pregnancy supports ongoing blood vessel health and may reduce high blood pressure risk.
Want to Apply This Research?
- Log daily folate intake through food and supplements, tracking sources like spinach, broccoli, lentils, and prenatal vitamins. Record weekly blood pressure readings if monitoring at home, noting any patterns related to dietary folate intake.
- Set a daily reminder to take prenatal vitamins containing folic acid. Add one folate-rich food to each meal (spinach in smoothies, beans in lunch, broccoli with dinner). Track these additions in the app to build the habit and monitor consistency.
- Create a weekly nutrition checklist tracking folate-rich foods consumed and prenatal vitamin adherence. Pair this with monthly blood pressure tracking if recommended by your healthcare provider. Share trends with your doctor at prenatal visits to discuss whether current folate intake is adequate.
This research describes associations between nutrient levels and pregnancy complications but does not establish cause and effect. Blood samples were collected after pregnancy, limiting the ability to determine whether low folate preceded high blood pressure. These findings should not replace standard prenatal care, blood pressure monitoring, or medical advice from your healthcare provider. If you have uterine fibroids or high blood pressure risk factors during pregnancy, discuss personalized nutrition and monitoring strategies with your obstetrician or midwife. This article is for educational purposes and should not be used for self-diagnosis or self-treatment.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.