Research shows that pregnant women with overweight or obesity who maintain healthy lifestyles, especially by not smoking and staying physically active, have better cholesterol levels and lower inflammation markers. According to Gram Research analysis of the PEARS trial involving 334 pregnant women, those with higher healthy lifestyle scores had significantly higher HDL cholesterol and lower IL-6 inflammation levels, with benefits extending to their newborns’ metabolic markers at birth.
A new study from the PEARS trial examined how pregnant women’s lifestyle choices affect their health and their babies’ health. Researchers looked at 334 women with overweight or obesity in early pregnancy and 285 in late pregnancy, tracking their diet, exercise, sleep, smoking, and alcohol use. According to Gram Research analysis, women who maintained healthier lifestyles, especially those who didn’t smoke and stayed physically active, had better cholesterol levels and lower inflammation markers. These benefits appeared to extend to their newborns as well, suggesting that prenatal lifestyle choices matter for both mother and baby’s metabolic health.
Key Statistics
A 2026 secondary analysis of the PEARS randomized controlled trial involving 334 pregnant women with overweight or obesity found that higher healthy lifestyle scores in early pregnancy were significantly associated with higher HDL cholesterol and lower IL-6 inflammation levels.
Among 334 pregnant women tracked in early pregnancy and 285 in late pregnancy, non-smoking status in early pregnancy was robustly associated with lower inflammatory markers, with benefits appearing in both maternal blood and newborn cord blood.
Research from the PEARS trial showed that physical activity and non-smoking status were the strongest components of prenatal healthy lifestyle scores, with consistent associations to improved lipid and inflammatory biomarkers across multiple statistical models.
The Quick Take
- What they studied: Whether pregnant women’s healthy lifestyle habits, like not smoking, exercising, eating well, sleeping enough, and avoiding alcohol, affect their blood chemistry and their baby’s blood chemistry at birth.
- Who participated: 334 pregnant women with overweight or obesity in early pregnancy and 285 of those same women in late pregnancy. These women were part of a larger research study called PEARS that tracked their health throughout pregnancy.
- Key finding: Women who had higher healthy lifestyle scores, particularly those who didn’t smoke and stayed physically active, had better HDL cholesterol (the good kind) and lower inflammation markers like IL-6. These benefits appeared in both the mothers and their newborns.
- What it means for you: If you’re pregnant or planning to become pregnant, maintaining healthy habits like not smoking, staying active, eating well, and getting good sleep may help protect your metabolic health and your baby’s health. However, this research shows associations, not definitive proof that these habits cause the improvements.
The Research Details
This was a secondary analysis of the PEARS randomized controlled trial, which means researchers used data that had already been collected from a larger study. They created a Healthy Lifestyle Score for each pregnant woman based on five factors: diet quality, physical activity level, alcohol use, smoking status, and sleep duration. They measured this score twice, once in early pregnancy and once in late pregnancy. The researchers then looked at blood tests from the mothers at both time points and from the babies’ umbilical cord blood at birth to see if women with higher lifestyle scores had healthier blood chemistry.
The researchers used a statistical method called linear regression to find connections between lifestyle scores and various blood markers. They looked at markers related to blood sugar control, cholesterol, inflammation, and fat metabolism. Because they were testing many different markers, they applied a correction method (Benjamini-Hochberg) to make sure they weren’t finding false connections just by chance.
This approach is valuable because it looks at lifestyle as a whole package rather than individual habits in isolation, which is more realistic since people don’t change just one thing at a time. The study focused specifically on pregnant women with overweight or obesity, a group that faces higher health risks during pregnancy.
Understanding how prenatal lifestyle affects both mother and baby is important because pregnancy is a critical time when the mother’s health directly influences the developing baby. The study’s focus on women with overweight or obesity matters because this group has higher risks of complications during pregnancy and metabolic problems after birth. By looking at multiple lifestyle factors together, researchers can give more practical advice than studying one factor alone.
This study has several strengths: it included a reasonable sample size (334 women initially), measured lifestyle factors at two different points in pregnancy, and looked at both maternal and infant outcomes. The researchers also tested their findings with statistical corrections to reduce false positives. However, the study relies on women self-reporting their lifestyle habits, which can be inaccurate. The study also lost some participants between early and late pregnancy (from 334 to 285), which is common but can affect results. The researchers note that many associations didn’t survive the statistical correction for multiple testing, suggesting some findings may not be as strong as they initially appeared.
What the Results Show
The strongest and most consistent finding was that women with higher healthy lifestyle scores in early pregnancy had higher HDL cholesterol, the type of cholesterol that protects heart health. This benefit was seen in both early and late pregnancy measurements. Additionally, women who didn’t smoke had significantly lower levels of IL-6, a marker of inflammation in the body. These benefits appeared to carry through to the babies as well, based on measurements from cord blood taken at birth.
Physical activity and smoking status emerged as particularly important components of the healthy lifestyle score. Women who were more physically active and those who didn’t smoke showed the most consistent improvements in inflammatory markers. The study found that these associations held up across different statistical models, meaning the findings were fairly robust.
Interestingly, the benefits weren’t limited to just the mothers. Babies born to women with higher healthy lifestyle scores, particularly those who didn’t smoke and stayed active, also showed better metabolic markers in their cord blood. This suggests that prenatal lifestyle may have lasting effects on the baby’s metabolic health from birth.
Several other associations were observed but were less consistent. Diet quality, sleep duration, and alcohol use showed some associations with metabolic markers, but these relationships were weaker and didn’t consistently hold up across all the statistical tests. The study found that some associations with inflammatory markers and physical activity levels appeared promising but didn’t survive the correction for multiple testing, meaning researchers can’t be as confident about these findings.
This research builds on growing evidence that prenatal lifestyle matters for both mother and baby. Previous studies have shown that individual factors like smoking and physical activity affect pregnancy outcomes, but this study is notable for looking at lifestyle as a comprehensive score. The findings align with existing research showing that smoking during pregnancy is particularly harmful and that physical activity provides protective benefits. The study adds to the evidence that these lifestyle factors affect not just birth outcomes but also the baby’s metabolic health markers at birth.
The study has several important limitations. First, women self-reported their lifestyle habits, which means the information may not be completely accurate. People often overestimate healthy behaviors and underestimate unhealthy ones. Second, the study lost participants between early and late pregnancy, dropping from 334 to 285 women, which could affect the results. Third, many of the associations found in initial analyses didn’t hold up after applying statistical corrections for multiple testing, suggesting some findings may have been false positives. Finally, this was a secondary analysis of existing data, so the original study wasn’t specifically designed to answer these questions. The study shows associations between lifestyle and metabolic markers but cannot prove that lifestyle changes cause the improvements.
The Bottom Line
Based on this research, pregnant women with overweight or obesity should prioritize not smoking and staying physically active during pregnancy. These two factors showed the strongest and most consistent benefits for metabolic health. Maintaining a healthy diet, getting adequate sleep, and avoiding alcohol are also supported by this research, though the evidence for these individual factors was less consistent. Women should discuss any exercise plans with their healthcare provider to ensure they’re appropriate for their individual pregnancy. Confidence level: Moderate for smoking cessation and physical activity; Lower for other lifestyle factors.
This research is most relevant for pregnant women with overweight or obesity, as that was the study population. However, the findings likely apply to all pregnant women since healthy lifestyle habits benefit everyone. Women planning to become pregnant should also pay attention to these findings, as prenatal health starts before pregnancy. Healthcare providers caring for pregnant women should use this research to encourage healthy lifestyle habits. This research is less relevant for women with normal weight, though healthy habits are still beneficial.
The metabolic benefits measured in this study were observed during pregnancy and at birth, so some changes may happen relatively quickly. However, pregnancy is only nine months, so expecting dramatic changes in metabolic markers may not be realistic. The most important timeline is that these habits need to be maintained throughout pregnancy to see consistent benefits. After pregnancy, continuing these healthy habits will support long-term health for both mother and baby.
Frequently Asked Questions
Does staying active during pregnancy help my baby’s health?
Research from the PEARS trial shows that pregnant women who stayed physically active had better cholesterol and lower inflammation markers, with benefits appearing in their newborns’ cord blood. Physical activity appears to be one of the most beneficial prenatal habits for metabolic health.
How does smoking during pregnancy affect my baby’s metabolism?
The PEARS study found that pregnant women who didn’t smoke had significantly lower inflammation markers (IL-6), and these benefits extended to their newborns. Smoking during pregnancy appears to increase inflammation in both mother and baby.
What lifestyle factors matter most during pregnancy for metabolic health?
According to the PEARS trial of 334 pregnant women, not smoking and staying physically active showed the strongest and most consistent benefits for metabolic markers. Diet, sleep, and avoiding alcohol also contributed to healthy lifestyle scores but showed weaker individual associations.
Can I improve my baby’s health by changing my lifestyle during pregnancy?
The PEARS study suggests that prenatal lifestyle habits may influence your baby’s metabolic health at birth. Babies born to women with higher healthy lifestyle scores had better metabolic markers in cord blood, though the study shows associations rather than definitive proof of causation.
Is it too late to start healthy habits in late pregnancy?
The PEARS trial measured lifestyle at both early and late pregnancy, finding benefits at both time points. While early pregnancy habits showed slightly stronger associations, maintaining healthy habits throughout pregnancy appears beneficial for both mother and baby’s metabolic health.
Want to Apply This Research?
- Track daily physical activity minutes, smoking status (zero cigarettes per day), sleep hours, and diet quality using a simple daily checklist. Calculate a weekly healthy lifestyle score by combining these factors, similar to how the research study did.
- Set a specific goal to increase weekly exercise by 30 minutes and eliminate smoking completely. Use the app to log each day you meet these goals and watch your healthy lifestyle score improve over the pregnancy weeks.
- Create a dashboard showing your healthy lifestyle score trend across pregnancy trimesters. Compare your early pregnancy score to late pregnancy score to see if you’re maintaining or improving your habits. Share this data with your healthcare provider at prenatal visits.
This research shows associations between prenatal lifestyle factors and metabolic markers but does not prove that lifestyle changes directly cause these improvements. Pregnant women should consult with their healthcare provider before making significant lifestyle changes, including starting new exercise programs. This information is not a substitute for medical advice. Women with specific pregnancy complications or health conditions should discuss these findings with their obstetrician or midwife. The study focused on women with overweight or obesity and may not apply equally to all pregnant populations.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.