A Diet High in Refined Grains and Low in Whole Grains in Pregnancy Linked to Lower Birthweights and Pre-term Births

Analyzing Diets Based on Racial and Ethnic Groups May Better Predict Outcomes

Authors: Luis E. Maldonado, et al.

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

Researchers wanted to understand how a pregnant person’s diet, especially in relation to their blood sugar levels (fasting blood glucose), affects birth outcomes—like the baby’s weight and whether the baby is born early. Higher fasting blood glucose during pregnancy is known to increase the risk of adverse birth outcomes. However, little is known about whether culturally influenced combinations of foods and beverages play a meaningful role across different racial and ethnic groups. This question is important because, in the U.S., Hispanic pregnant women are disproportionately affected by adverse birth outcomes, such as preterm birth and low birthweight (under 5.5 pounds). By examining dietary patterns within racial and ethnic groups, the researchers aimed to uncover more precise links between diet and birth outcomes. These links might be overlooked when analyzing the population as a whole, since average diets often reflect the eating patterns of the most represented groups in the study.

What were the study results?

Refined grains, such as white bread or white rice, showed the strongest association with higher fasting blood sugar levels among Hispanic and non-Hispanic White women. People who ate diets high in refined grains and low in whole grains were more likely to have babies born with low birthweight, smaller for gestational age, or born preterm.

When dietary patterns were analyzed by racial and ethnic group, the associations between diet, blood sugar, and birth outcomes were stronger than when using a single pattern for the full population. In the group that included non-Hispanic White and Hispanic participants, nuts, seeds, and solid fats such as butter and lard were linked to lower blood sugar. Among non-Hispanic White participants, whole grains and solid fats had the strongest association with improved blood sugar control. In contrast, among Hispanic participants, higher fruit consumption was associated with elevated blood sugar levels. These food-specific associations should be considered within the overall dietary pattern, as individual foods can influence blood sugar – beneficially or adversely – within the broader diet.

What was the study's impact?

The results of this study show the importance of looking at dietary patterns within racial and ethnic groups, particularly in studies with varying representation of different racial and ethnic populations. Analyzing a single, combined group may mask group-specific associations between diet and birth outcomes, as the effects of diet can differ across racial and ethnic backgrounds.

Who was involved?

The study included 420 Hispanic and 564 non-Hispanic White pregnant participants from two ECHO Cohort study sites.

What happened during the study?

During the study, participants shared details about what they ate over a 24-hour period. The researchers analyzed the diets, along with the mother’s blood sugar, to help determine which combinations of foods eaten together in an overall diet are most closely linked to changes in blood sugar levels. They then tested whether the links between diet and birth outcomes were different across racial and ethnic groups by comparing findings from diets derived using group-specific versus combined fasting blood glucose, which have also been previously shown to vary by racial and ethnic population.

Footnote: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What happens next?

Future research could continue exploring how dietary patterns affect birth outcomes in diverse populations, especially by identifying patterns that are specific to different racial and ethnic groups.

Where can I learn more?

Access the full journal article, titled “Racial/Ethnic-Derived Maternal Diets Predict Birth Outcomes Better than a Diet Derived from a Combined Sample among Hispanic/Latina and non-Hispanic White Pregnant Individuals in the ECHO Cohort,” in Nutrition.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published June 12, 2025

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A Diet High in Refined Grains and Low in Whole Grains in Pregnancy Linked to Lower Birthweights and Pre-term Births

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Pregnancy and birth

ECHO Study Investigates Pollution Exposure and Birth Outcomes in Pregnant Women Living in Historically Redlined Neighborhoods

Authors: Teresa Herrera, Akhgar Ghassabian, et al.

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

Exposure to tiny air pollutants known as PM2.5 during pregnancy can lead to outcomes like low birth weight and preterm birth. Factors such as weather, government policies, and social conditions can affect how much exposure pregnant women have to these pollutants. One factor that may have affected exposure is redlining, the historical practice of designating certain neighborhoods, often where minority groups lived, as risky investments for lenders. This grading system ranked neighborhoods on an A through D scale—A being the most desirable—which often led to disinvestment and lack of resources in lower-rated areas. While redlining was made illegal following the 1968 Fair Housing Act, it continues to affect the health outcomes of people living in historically redlined areas.

ECHO researchers wanted to learn whether living in historically redlined areas during pregnancy affects air pollution exposure and birth outcomes in New York City (NYC). Understanding what influences PM2.5 levels and their impact on birth outcomes can help improve the health of mothers and their children.

What were the study results?

The study found that living in lower-graded or ungraded census tracts during pregnancy was associated with higher exposure to PM2.5. These women also tended to have babies with lower birth weights. This association was strong even when considering factors such as race, ethnicity, and income at individual and community levels.

What was this study's impact?

The study supports the literature linking redlining to contemporary outcomes. This study highlights the multifaceted nature of structural racism. Findings from non-graded areas indicate that there are likely additional factors, along with redlining, that play a role in perpetuating modern-day inequality.

Who was involved?

The participants were 3,160 pregnant mothers and their babies in the NYC metropolitan area who were enrolled in six ECHO Cohort research sites. The study included pregnant mothers from 2005 to 2022 who had air pollution estimates available for their residential address. Most participants who identified as Black or White lived in neighborhoods that had been given a D grade, the lowest rating. Most participants who identified as Hispanic lived in neighborhoods with B or C grades.

What happened during the study?

Researchers used statistical methods to explore whether living in neighborhoods that were historically redlined was associated with higher exposure to air pollution (PM2.5) during pregnancy. They also examined if living in these neighborhoods was associated with the baby's birth weight, the likelihood of being born early, and the chances of having a low birth weight.

Note: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What happens next?

The authors note that future research could look at other practices like racial exclusionary zoning to fully understand the ongoing systemic effects of redlining.

Where can I learn more?

Access the full journal article, titled “Redlining in New York City: Impacts on Particulate Matter Exposure During Pregnancy and Birth Outcomes,” in Journal of Epidemiology and Community Health.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published September 5, 2024

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ECHO Study Investigates Pollution Exposure and Birth Outcomes in Pregnant Women Living in Historically Redlined Neighborhoods

Depression in New Mothers Is Common, Especially When Babies Are Born Too Early

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Depression in New Mothers Is Common, Especially When Babies Are Born Too Early

Author(s): Nicole Bush, Danielle Roubinov, Rashelle Musci, et al.

Who sponsored this study?

This research was supported by the Environmental influences on Child Health Outcomes (ECHO) program, Office of The Director, National Institutes of Health.

Footnote: The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

What were the study results?

During the first five years following childbirth, one out of every five mothers who gave birth to a preterm baby had symptoms of depression, while one out of every ten mothers who gave birth to a full-term baby had symptoms of depression. For mothers of preterm infants, it was also more common to have symptoms that got worse over time compared to women who gave birth to full-term babies. The most severe symptoms of depression were seen in women who gave birth early.

Footnote: Results reported here are for a single study. Other or future studies may provide new information or different results. You should always consult with a qualified healthcare provider for diagnosis and for answers to your personal questions.

What was the study's impact?

This study supports previous reports that many mothers struggle with their mental health after giving birth, and women who have preterm babies may be particularly at risk for symptoms of depression—such as sadness, stress, anxiety, and feelings of being overwhelmed. Maternal mental health can influence their child’s health and development. Right now, doctors only screen women for depression symptoms when they are pregnant and for six months after they have their babies. This study shows that some women continue to struggle with depression for years after they give birth or start experiencing depression when their children are older. This trend was especially true for women whose babies were born prematurely. This study shows the importance of asking women about their mental health for much longer than six months after they give birth and helping them find supportive interventions.

Why was this study needed?

The postpartum period can be especially hard for mothers when babies are born prematurely, but researchers don’t know much about the effect that preterm births can have on a mother’s mental health. This study assessed postpartum depressive symptom trajectories for mothers of preterm and full-term babies, and followed participating mothers for five years after birth to better understand the long-term risks for depression and potential opportunities for treatment.

Who was involved?

The study involved 11,320 pregnant women aged 18 to 52 years old from 35 ECHO cohorts across the United States. About 11% of these women had babies that were born before they were due (preterm infants) and 89% had babies that were born on or near their due date (full-term infants).

What happened during the study?

Researchers analyzed self-reported depression measurements for women when they were pregnant and after they had their babies. These women also completed at least one follow-up assessment before their children were 5 years old.

What happens next?

It is important for future research to study what factors put some women at higher risk of experiencing depression after giving birth, particularly mothers of premature babies. Future research should also investigate what types of programs can help support mothers and their mental health during pregnancy and after birth.

Where can I learn more?

Access the full journal article titled, “Trajectories of Depressive Symptoms Among Mothers of Preterm and Full-Term Infants in a National Sample” in Archives of Women's Mental Health.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published June 16, 2022

Access the associated article.

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Depression in New Mothers Is Common, Especially When Babies Are Born Too Early