A large study of 3,587 pregnant women who used fertility treatments found that taking high doses of vitamin E supplements (over 100 mg daily) during early pregnancy increased their risk of developing dangerous high blood pressure conditions by 68%. This risk was especially high for women who already got enough vitamin E from their regular diet. The researchers used blood tests to confirm their findings, showing that too much vitamin E in the body was linked to pregnancy complications. Getting vitamin E from food didn’t cause problems - only the high-dose pills did.

The Quick Take

  • What they studied: Whether taking vitamin E supplements during early pregnancy increases the risk of developing high blood pressure conditions that can be dangerous for both mom and baby
  • Who participated: 3,587 pregnant women in China who used fertility treatments like IVF and were at least 20 weeks pregnant
  • Key finding: Women taking more than 100 mg of vitamin E supplements daily had a 68% higher chance of developing pregnancy-related high blood pressure compared to those who didn’t take supplements
  • What it means for you: If you’re pregnant or planning to be, talk to your doctor before taking vitamin E supplements, especially if you already eat a healthy diet with vitamin E-rich foods

The Research Details

Researchers followed 3,587 pregnant women who had used assisted reproductive technology (like IVF) to get pregnant. They collected detailed information about what the women ate and what supplements they took using questionnaires. The scientists also took blood samples during the first three months of pregnancy to measure vitamin E levels in the body. They then tracked which women developed gestational hypertension (high blood pressure during pregnancy) or preeclampsia (a more serious condition with high blood pressure and protein in urine) by reviewing their medical records. The study separated vitamin E from food versus vitamin E from pills to see which one might cause problems. They also used advanced blood testing called metabolomics to look at how the body processes vitamin E and whether certain breakdown products were linked to high blood pressure problems.

This type of study design is important because it follows women over time and measures actual vitamin E levels in their blood, not just what they reported eating or taking. This gives us more reliable information about cause and effect.

The study was large with nearly 3,600 women, used objective blood tests to confirm vitamin E levels, and carefully separated the effects of food versus supplements. However, it only looked at women who used fertility treatments, so the results might not apply to all pregnant women.

What the Results Show

The study found that getting vitamin E from food was completely safe and didn’t increase any pregnancy risks. However, taking vitamin E supplements was a different story. Women who took more than 100 mg of vitamin E supplements daily during early pregnancy had a 68% higher risk of developing gestational hypertension or preeclampsia compared to women who didn’t take supplements. The risk was especially high for women who took supplements for more than 2 months or consumed more than 12,000 mg total. The researchers found that the timing mattered too - taking these high doses during the critical early months of pregnancy seemed to be when the damage occurred. Blood tests confirmed these findings by showing that women with higher levels of vitamin E breakdown products in their blood were 55% more likely to develop high blood pressure problems during pregnancy.

The study revealed that a woman’s regular diet played an important role in determining supplement safety. Women who already ate foods rich in vitamin E (like nuts, seeds, and vegetable oils) had increased risks even with lower supplement doses of 100 mg or less. For women with low dietary vitamin E intake, problems only appeared with doses above 100 mg daily. This suggests that the total amount of vitamin E in the body matters more than just the supplement dose alone.

Previous research on vitamin E and pregnancy has shown mixed results, with some studies suggesting benefits and others showing no effect. This study helps explain the confusion by showing that the source of vitamin E (food versus pills) and the total amount in the body are crucial factors that earlier studies may not have considered carefully enough.

The study only included women who used fertility treatments, so we don’t know if the same risks apply to women who got pregnant naturally. The research was done in China, so dietary patterns and supplement formulations might be different in other countries. Also, the study couldn’t account for every possible factor that might influence pregnancy complications, though the researchers tried to control for the most important ones.

The Bottom Line

Pregnant women should be very cautious about taking vitamin E supplements, especially doses above 100 mg daily. Focus on getting vitamin E from healthy foods like nuts, seeds, vegetable oils, and leafy greens instead of pills. If you’re already taking a prenatal vitamin, check the vitamin E content and discuss with your doctor whether additional supplements are necessary.

This is most relevant for pregnant women, women trying to conceive, and those who used fertility treatments. Women who already eat a diet rich in vitamin E-containing foods should be especially careful about adding supplements.

The increased risks appeared to develop during early pregnancy when supplements were taken, suggesting that avoiding high-dose supplements from conception through the first trimester is most important.

Want to Apply This Research?

  • Log your daily vitamin E intake from both food sources and supplements, aiming to stay under 100 mg total daily from supplements
  • Replace high-dose vitamin E supplements with vitamin E-rich whole foods like almonds, sunflower seeds, and spinach
  • Track blood pressure readings weekly during pregnancy and note any correlation with supplement intake patterns

This information is for educational purposes only and should not replace professional medical advice. Always consult with your healthcare provider before starting, stopping, or changing any supplements during pregnancy, especially if you have used fertility treatments or have risk factors for pregnancy complications.