Researchers wanted to know if eating lots of sugary foods during pregnancy could cause preeclampsia, a serious condition where pregnant women develop high blood pressure. They studied 1,146 pregnant women and found that those who ate sweets three or more times per week had higher rates of this condition. However, when scientists used genetic information to test whether sweets actually cause the problem, they found something surprising: the real culprit appears to be extra body weight, not the sweets themselves. This suggests that what matters most is maintaining a healthy weight during pregnancy.

The Quick Take

  • What they studied: Whether eating sweet foods frequently during pregnancy increases the risk of preeclampsia, a condition where pregnant women develop dangerously high blood pressure.
  • Who participated: 1,146 pregnant women from a hospital in China, including 60 women who developed preeclampsia and 1,086 women who didn’t. Researchers looked back at their eating habits before delivery.
  • Key finding: Women who ate sweets three or more times per week were 2.5 times more likely to develop preeclampsia compared to those who ate sweets less often. However, genetic analysis suggested this connection wasn’t directly caused by the sweets themselves, but rather by weight gain.
  • What it means for you: If you’re pregnant or planning to become pregnant, focusing on maintaining a healthy weight appears more important than strictly avoiding sweets. However, eating fewer sugary foods is still a good idea because it helps prevent weight gain and supports overall health during pregnancy.

The Research Details

This study used two different research methods to answer the same question. First, researchers conducted a case-control study by comparing 60 pregnant women who developed preeclampsia with 1,086 women who didn’t. They looked back at what these women ate before delivery, specifically asking about sweet food consumption (eating sweets three or more times per week). They then used statistical methods to account for other factors that might affect the results, like age, weight before pregnancy, blood sugar levels, and anemia.

Second, the researchers used a more advanced genetic method called Mendelian randomization. This method uses genetic information from large databases (UK Biobank and FinnGen) to determine whether sweet food consumption actually causes preeclampsia or if the connection is just coincidental. This genetic approach is valuable because it can help separate true cause-and-effect relationships from associations that happen by chance.

The combination of these two methods provides stronger evidence than either method alone, though neither method is perfect.

The case-control study shows what happens in real life, but it can’t prove that sweets cause preeclampsia because many other factors could explain the connection. The genetic analysis helps answer the ‘does it actually cause it?’ question more definitively. Together, these methods help researchers understand whether dietary recommendations should focus on reducing sweets or on managing weight.

The study’s strengths include a reasonably large sample size (1,146 women) and the use of two complementary research methods. The researchers also adjusted for important factors like age and blood sugar that could affect results. However, the study has limitations: only 60 women developed preeclampsia (a relatively small number), the study was conducted in one hospital in China (results may differ in other populations), and dietary information was collected after pregnancy ended, which could introduce memory errors. The genetic analysis relied on data from European populations, which may not perfectly apply to the Chinese women in the study.

What the Results Show

In the case-control study, women who ate sweets three or more times per week were 2.51 times more likely to develop preeclampsia compared to women who ate sweets less frequently. This difference was statistically significant, meaning it’s unlikely to have happened by chance. After adjusting for other factors like age, pre-pregnancy weight, blood glucose, and anemia, this increased risk remained strong.

However, the genetic analysis (Mendelian randomization) told a different story. When researchers used genetic information to test whether sweet food consumption directly causes preeclampsia, they found no causal relationship. This suggests that the connection seen in the case-control study might be explained by other factors, particularly weight gain.

The genetic analysis did identify a clear causal link between higher body mass index (BMI, a measure of weight relative to height) and preeclampsia. For every unit increase in BMI, the risk of preeclampsia increased by 56%. This was a very strong and statistically significant finding, suggesting that weight management is crucial during pregnancy.

The study highlights that the relationship between diet and preeclampsia is more complex than initially thought. The association between sweets and preeclampsia in the case-control study likely reflects the fact that eating more sweets leads to weight gain, and weight gain is the actual risk factor. This finding emphasizes that pregnant women should focus on overall calorie intake and weight management rather than eliminating specific foods. The research also suggests that metabolic health during pregnancy, influenced by weight and energy intake, plays a central role in preeclampsia development.

Previous research has suggested links between sugar consumption and various pregnancy complications, but this study provides important nuance. While earlier studies sometimes focused on specific nutrients or foods, this research demonstrates that the broader picture of weight management may be more important. The finding that BMI is a strong causal factor aligns with existing medical knowledge that obesity increases pregnancy risks. This study adds to growing evidence that weight-related factors, rather than specific dietary components, are primary drivers of preeclampsia risk.

The study has several important limitations. First, only 60 women developed preeclampsia out of 1,146, which is a small number for drawing firm conclusions. Second, dietary information was collected after pregnancy ended, so women might not remember exactly what they ate months earlier. Third, the study was conducted in one hospital in China, so results may not apply to pregnant women in other countries or populations. Fourth, the genetic analysis used data primarily from European populations, which may not perfectly represent the genetic patterns in the Chinese women studied. Finally, the study couldn’t account for all possible factors that might influence preeclampsia risk, such as physical activity, stress, or sleep quality.

The Bottom Line

Based on this research, pregnant women should prioritize maintaining a healthy weight during pregnancy rather than focusing solely on avoiding sweets. This can be achieved by eating balanced meals with appropriate portion sizes and staying physically active (as approved by your doctor). While reducing sugary foods is still beneficial because it helps prevent excessive weight gain and supports overall health, the key message is that total calorie intake and weight management matter more than eliminating specific foods. These recommendations have moderate confidence because the genetic analysis didn’t confirm that sweets directly cause preeclampsia, but weight management is well-established as important for pregnancy health.

These findings are most relevant to pregnant women and women planning pregnancy, particularly those who are overweight or have a family history of preeclampsia. Healthcare providers should use this information to counsel pregnant patients about weight management rather than strict dietary restrictions. Women with gestational diabetes or other metabolic conditions should pay special attention to weight management. However, these findings may not apply equally to all populations, as the study was conducted in China and genetic data came primarily from European populations.

Weight management benefits during pregnancy develop gradually throughout the nine months of pregnancy. The risk of preeclampsia increases as pregnancy progresses, particularly in the third trimester. Women should aim for steady, appropriate weight gain throughout pregnancy (typically 25-35 pounds for women of normal weight before pregnancy) rather than rapid gains. Benefits of maintaining healthy weight become apparent through regular blood pressure monitoring and blood work throughout pregnancy, with the most critical period being the third trimester.

Want to Apply This Research?

  • Track weekly weight gain and sweet food consumption frequency (number of times per week eating sugary foods). Record this alongside blood pressure readings if available. Aim for steady weight gain of about 0.5-1 pound per week in the second and third trimesters, and monitor whether reducing sweet food frequency helps maintain appropriate weight gain.
  • Set a specific goal to reduce sweet food consumption from current frequency to no more than 1-2 times per week. Replace sugary snacks with protein-rich or fiber-rich alternatives (nuts, yogurt, fruit, whole grains). Log each instance of sweet food consumption and note the weight impact over 2-4 week periods to see the connection between dietary choices and weight gain.
  • Use the app to track weekly weight trends rather than daily fluctuations, as pregnancy weight naturally varies. Create a dashboard showing the relationship between sweet food frequency and weight gain patterns. Set reminders for regular prenatal appointments where blood pressure is monitored. Track energy intake and physical activity alongside weight to maintain a holistic view of metabolic health during pregnancy.

This research provides insights into the relationship between diet, weight, and preeclampsia, but it should not replace personalized medical advice from your healthcare provider. Preeclampsia is a serious condition that requires professional medical monitoring throughout pregnancy. All dietary and lifestyle changes during pregnancy should be discussed with your obstetrician or midwife, as individual circumstances vary. This study was conducted in a specific population and may not apply equally to all pregnant women. If you have concerns about preeclampsia risk, high blood pressure, or appropriate weight gain during pregnancy, consult your healthcare provider immediately. This information is for educational purposes and does not constitute medical advice.