Researchers studied 812 pregnant women to see if eating more ultra-processed foods (like packaged meals and snacks) during pregnancy increased the risk of preeclampsia, a serious blood pressure condition. Women who significantly increased their processed food intake between their second and third trimester had about 2.3 times higher risk of developing preeclampsia compared to those who didn’t increase their intake as much. This finding suggests that pregnant women, especially those already at higher risk, might benefit from choosing fresher, less processed foods during pregnancy.
The Quick Take
- What they studied: Whether eating more ultra-processed foods (packaged, pre-made meals and snacks) during pregnancy increases the chance of developing preeclampsia, a dangerous blood pressure condition that can harm both mom and baby.
- Who participated: 812 pregnant women in Barcelona, Spain who were already considered at higher risk for having smaller babies. Researchers tracked their food choices at two points during pregnancy: around week 20 and again around week 35.
- Key finding: Women who ate significantly more ultra-processed foods in their third trimester had about 2.3 times higher risk of preeclampsia compared to women who didn’t increase their processed food intake. Pre-prepared dishes (like frozen meals) showed the strongest connection.
- What it means for you: If you’re pregnant or planning to become pregnant, especially if you’re at higher risk for pregnancy complications, reducing ultra-processed foods and choosing fresher options may help lower your preeclampsia risk. However, this is one study in a specific group, so talk with your doctor about your individual situation.
The Research Details
This study used data from a larger pregnancy research project called IMPACT BCN that included over 1,200 pregnant women. The researchers focused on 812 women who had complete information about what they ate at two different times during pregnancy. They used a detailed food questionnaire with 151 different foods to measure how much ultra-processed food each woman ate. Ultra-processed foods were identified using a classification system called NOVA, which sorts foods by how much processing they’ve gone through.
The researchers divided women into three groups based on how much their ultra-processed food intake changed from the second trimester (around week 20) to the third trimester (around week 35). They then compared preeclampsia rates between these groups. Preeclampsia was defined as high blood pressure combined with signs of organ damage, which doctors confirmed through medical records.
The analysis carefully controlled for other factors that might affect preeclampsia risk, such as age, weight, education level, and other dietary factors. This helps ensure that the connection they found was actually about ultra-processed foods and not something else.
This research approach is important because it looks at how changes in eating habits during pregnancy affect health outcomes, rather than just looking at one point in time. Pregnancy is a critical window when what a woman eats can significantly impact both her health and her baby’s development. By tracking food intake at two different times, researchers could see if increasing processed food consumption specifically during the later stages of pregnancy mattered.
This study has several strengths: it’s based on a randomized clinical trial (a gold-standard research design), it included a reasonably large group of women, and it carefully measured food intake using a validated questionnaire. However, the study was conducted in one city in Spain, so results might not apply equally to all populations. The study also looked at women already at higher risk, so findings may not apply to all pregnant women. Additionally, the connection between ultra-processed foods and preeclampsia was only clear when women were divided into groups; when analyzed as a continuous change, the relationship wasn’t statistically significant, which suggests the effect may be more complex than initially appears.
What the Results Show
Women who increased their ultra-processed food consumption the most (highest third) had 2.29 times the risk of preeclampsia compared to women who increased it the least (lowest third). This difference was statistically significant, meaning it’s unlikely to be due to chance alone. However, when researchers looked at ultra-processed food increase as a continuous measure (rather than dividing women into groups), the relationship was no longer statistically significant.
Among different types of ultra-processed foods, pre-prepared dishes (like frozen meals and ready-to-eat foods) showed the strongest connection to preeclampsia risk. Women in the highest consumption group for these foods had 2.36 times the risk compared to those in the lowest group.
These findings suggest that the timing and type of ultra-processed food consumption during pregnancy may matter. The increase in risk was specifically associated with eating more of these foods in the later stages of pregnancy (third trimester), not earlier in pregnancy.
The study examined various ultra-processed food subcategories. While pre-prepared dishes showed the strongest association with preeclampsia, the researchers also looked at other types of ultra-processed foods. The fact that pre-prepared dishes specifically stood out suggests that certain characteristics of these foods—possibly their sodium content, additives, or other components—might be particularly relevant to preeclampsia risk.
Previous research has shown that ultra-processed foods are linked to various health problems like obesity, diabetes, and heart disease. However, research specifically looking at ultra-processed foods and pregnancy outcomes has been limited. This study adds important new evidence by showing that the connection between processed foods and health problems may extend to pregnancy complications. The findings align with broader nutritional science suggesting that whole, minimally processed foods are generally healthier during pregnancy.
This study has several important limitations to consider. First, it only included women already at higher risk for pregnancy complications, so results may not apply to all pregnant women. Second, the study was conducted in Barcelona, Spain, so dietary patterns and food availability might differ in other regions. Third, women self-reported their food intake, which can be subject to memory errors or bias. Fourth, the researchers couldn’t prove that ultra-processed foods directly caused preeclampsia—only that there was an association. Finally, the relationship wasn’t consistent when analyzed as a continuous variable, suggesting the effect may be more nuanced than the grouped analysis suggests.
The Bottom Line
Based on this research, pregnant women—particularly those at higher risk for complications—may benefit from limiting ultra-processed foods, especially pre-prepared dishes, particularly in the later stages of pregnancy. Instead, focus on whole foods like fresh fruits, vegetables, whole grains, and fresh proteins. However, this is one study, so these recommendations should be considered alongside guidance from your healthcare provider. Confidence level: Moderate—the findings are promising but need confirmation in larger, more diverse populations.
This research is most relevant to pregnant women, especially those at higher risk for pregnancy complications. Women with a history of high blood pressure, obesity, or previous pregnancy complications should pay particular attention. Healthcare providers caring for pregnant women should also consider these findings when discussing nutrition. However, all pregnant women can benefit from reducing ultra-processed foods as part of a healthy pregnancy diet. This doesn’t apply to non-pregnant individuals, though the general principle of limiting ultra-processed foods is beneficial for everyone.
If you reduce ultra-processed food intake during pregnancy, you wouldn’t necessarily see immediate changes in blood pressure or preeclampsia risk. However, dietary changes typically begin affecting blood pressure and inflammation markers within weeks to months. Since preeclampsia typically develops in the third trimester, making dietary changes earlier in pregnancy may be most beneficial. The protective effect would likely be most noticeable if changes are maintained throughout the second and third trimesters.
Want to Apply This Research?
- Track the number of ultra-processed food servings consumed daily, with specific focus on pre-prepared/frozen meals. Set a goal to reduce these by 25-50% and monitor weekly trends. Include categories like: frozen meals, packaged snacks, sugary drinks, and processed meats.
- Replace one ultra-processed food item per day with a whole food alternative. For example: swap frozen dinners for home-cooked meals, replace packaged snacks with fresh fruit or nuts, or substitute sugary drinks with water or herbal tea. Start with one meal or snack and gradually expand.
- Weekly check-ins on ultra-processed food intake with visual progress tracking. Create a ‘clean eating’ streak counter to maintain motivation. Log blood pressure readings if monitoring at home (with doctor approval). Track energy levels and any pregnancy-related symptoms to correlate with dietary changes.
This research suggests an association between increased ultra-processed food consumption and preeclampsia risk in pregnant women, but does not prove causation. This information is for educational purposes only and should not replace professional medical advice. Pregnant women should discuss their diet and any concerns about preeclampsia risk with their healthcare provider. If you experience symptoms of preeclampsia—such as high blood pressure, severe headaches, vision changes, or upper abdominal pain—seek immediate medical attention. Individual risk factors and dietary needs vary; personalized guidance from your doctor or a registered dietitian is essential for your specific situation.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.