The GROWTH Study, a longitudinal cohort research project enrolling women from October 2023 through December 2026, is investigating how maternal blood sugar levels during pregnancy affect the nutrient composition of breast milk and infant growth patterns. According to research reviewed by Gram, this study measures maternal glucose tolerance at 24-28 weeks of pregnancy and tracks breast milk fatty acid content and infant body composition through age 2, potentially revealing how pregnancy metabolism continues to influence babies’ development through breastfeeding.
A new study called GROWTH is tracking how a mother’s blood sugar levels during pregnancy might affect the nutrients in her breast milk and how her baby grows. Researchers are following pregnant women from October 2023 through 2026, measuring their blood sugar, collecting samples of their breast milk at different times, and tracking their babies’ growth until age 2. This research could help doctors understand how what happens during pregnancy continues to influence a baby’s health through breast milk, potentially affecting whether children develop weight or body composition issues later in life.
Key Statistics
The GROWTH Study, a cohort study enrolling pregnant women starting October 2023, is measuring maternal blood sugar via glucose tolerance testing at 24-28 weeks of gestation to determine how it affects breast milk composition and infant growth through age 2.
According to the GROWTH Study protocol published in BMJ Open in 2026, researchers are collecting breast milk samples at three time points postpartum to measure linoleic acid and docosahexaenoic acid (DHA) concentrations in relation to maternal glycemia during pregnancy.
The GROWTH Study includes comprehensive data collection on maternal and infant blood samples, serial growth measurements, and dietary assessments to understand how pregnancy metabolism programs infant body composition through breast milk during the first two years of life.
The Quick Take
- What they studied: Whether a mother’s blood sugar levels during pregnancy change the nutrients in her breast milk, and if those changes affect how babies grow and develop their body composition during the first two years of life.
- Who participated: Pregnant women expecting a single baby who plan to breastfeed (either directly or by pumping) and their infants, enrolled starting October 2023 with enrollment expected to finish in December 2026.
- Key finding: This is a study protocol describing how researchers will collect data on maternal blood sugar, breast milk composition, and infant growth—the actual results will be published after the study completes in 2026.
- What it means for you: This research may eventually help explain why some babies born to mothers with higher blood sugar during pregnancy develop different body compositions, potentially informing better prenatal and postpartum care recommendations.
The Research Details
The GROWTH Study is a longitudinal cohort study, which means researchers follow the same group of people over time and collect information at multiple points. Women enrolled in the study undergo blood sugar testing (called an oral glucose tolerance test) between weeks 24-28 of pregnancy, which is the standard screening time for gestational diabetes. Researchers then collect breast milk samples at three different time points after the baby is born, along with blood samples from both mother and baby, and measurements of how much the baby weighs and grows.
This design is powerful because it allows researchers to see how maternal blood sugar during pregnancy connects to the actual composition of breast milk—specifically looking at important fatty acids like linoleic acid and docosahexaenoic acid (DHA), which are crucial for brain development. By following babies until age 2, the study can track early growth patterns that might predict later health issues.
The study includes virtual lactation support visits to help mothers with breastfeeding, and researchers also assess what mothers and babies eat. This comprehensive approach captures the full picture of how pregnancy metabolism might program a child’s growth trajectory through breast milk.
Most research on how pregnancy affects a baby’s future health focuses on what happens in the womb. However, breastfeeding continues this connection after birth—breast milk carries signals from the mother’s body that can influence how a baby’s body develops. By measuring both maternal blood sugar and breast milk composition together, this study can show whether and how pregnancy metabolism actually changes breast milk in ways that matter for babies’ growth. This is important because early growth patterns are linked to obesity and metabolic disease risk later in life.
This is a protocol paper, meaning it describes the study plan before results are available. The study is being conducted at a major children’s hospital (Lurie Children’s Hospital) with institutional oversight, which ensures ethical standards and data quality. The study’s strength lies in its comprehensive measurements—collecting multiple types of data (blood sugar, milk composition, growth measurements, diet) from both mothers and babies over time. The main limitation at this stage is that we don’t yet have results; the actual findings will be published after December 2026.
What the Results Show
This is a protocol paper published in April 2026 describing a study that is still ongoing. The primary goal is to measure how maternal blood sugar during pregnancy (measured at 24-28 weeks of gestation using a glucose tolerance test) relates to the fatty acid content of breast milk collected one month after delivery. The study will examine two specific fatty acids: linoleic acid and docosahexaenoic acid (DHA), both of which are essential for infant brain development and growth.
The researchers are collecting data from pregnant women who plan to breastfeed, tracking them and their babies through the first two years of life. This timing is crucial because the first two years are when growth patterns are established that can influence long-term health outcomes. The study began enrolling participants in October 2023 and expects to complete enrollment by December 2026, meaning actual results will be published after that date.
Beyond the primary focus on breast milk fatty acids, the GROWTH Study is also collecting data on infant growth patterns, body composition (how much of a baby’s weight is fat versus muscle), and maternal metabolic markers. These secondary measurements will help researchers understand the broader picture of how maternal metabolism during pregnancy influences infant development through breastfeeding. The study also includes dietary assessments for both mothers and infants, which can help explain variations in growth and body composition.
Previous research has shown that maternal blood sugar during pregnancy affects infant birth weight and later obesity risk, but most of this research doesn’t explain the mechanism—how does pregnancy metabolism actually change things after birth? The GROWTH Study fills this gap by measuring breast milk composition, which is the direct biological link between maternal metabolism and infant nutrition after birth. This is a novel approach because few studies have simultaneously measured maternal glycemia (blood sugar control), breast milk composition, and infant growth outcomes.
As a protocol paper, the main limitation is that results are not yet available. Once the study completes, potential limitations may include: the study focuses only on women who plan to breastfeed, so results may not apply to formula-feeding families; enrollment is at specific medical centers, so the population studied may not represent all pregnant women; and the study follows children only until age 2, so long-term effects on later childhood obesity or metabolic disease cannot yet be determined. Additionally, maternal blood sugar is measured at one time point (24-28 weeks), so it may not capture the full picture of blood sugar control throughout pregnancy.
The Bottom Line
This is a protocol paper, so clinical recommendations cannot yet be made. However, once results are available (expected after December 2026), this research may inform recommendations about blood sugar management during pregnancy and its importance for breastfeeding outcomes. Current evidence suggests maintaining healthy blood sugar during pregnancy is important for both immediate and long-term infant health, and this study will provide more specific information about the breast milk mechanisms involved.
Pregnant women, especially those with elevated blood sugar or gestational diabetes, should follow this research as it develops. Healthcare providers managing pregnancy and postpartum care should also pay attention to these findings, as they may change recommendations about blood sugar screening and management. Parents interested in understanding how pregnancy health affects infant development through breastfeeding will find this research relevant.
This study is still enrolling participants (expected through December 2026) and following children until age 2. Results will likely be published in 2027-2028. Any changes to clinical practice based on these findings would likely take additional time for review and implementation, so practical applications may not be available for 2-3 years.
Frequently Asked Questions
Does maternal blood sugar during pregnancy affect breast milk composition?
The GROWTH Study is specifically designed to answer this question by measuring maternal blood sugar at 24-28 weeks of pregnancy and analyzing breast milk fatty acids postpartum. Results will be available after December 2026, but the study hypothesis suggests maternal glycemia does influence milk composition.
How does breast milk carry signals from pregnancy metabolism to babies?
Breast milk contains specific nutrients and compounds that reflect maternal metabolism, including fatty acids like DHA that are essential for infant brain development. The GROWTH Study measures these components to show the biological connection between pregnancy health and infant nutrition through breastfeeding.
Can high blood sugar during pregnancy affect my baby’s growth after birth?
Research suggests maternal blood sugar during pregnancy may influence infant growth patterns and body composition, potentially through changes in breast milk composition. The GROWTH Study will provide specific evidence about this mechanism once results are published after December 2026.
Should I get blood sugar testing during pregnancy?
Standard prenatal care includes glucose tolerance testing at 24-28 weeks of pregnancy to screen for gestational diabetes. The GROWTH Study emphasizes the importance of this testing, as blood sugar control during pregnancy may influence infant health through breastfeeding and early growth patterns.
How long does it take to see effects of maternal blood sugar on infant growth?
The GROWTH Study follows infants until age 2, as early growth patterns during this period are most influenced by breast milk composition and maternal metabolism. Long-term effects on childhood obesity or metabolic disease cannot yet be determined from this study design.
Want to Apply This Research?
- Once results are available, pregnant women could track their blood sugar levels (if tested) alongside notes about their breastfeeding status and any lactation support received, creating a personal record of how their pregnancy metabolism might relate to their milk production.
- Based on this emerging research, pregnant women could prioritize regular blood sugar screening during pregnancy (24-28 weeks) and discuss results with their healthcare provider, while also planning to breastfeed if possible, as breast milk may be an important way pregnancy health influences infant development.
- After the study results are published, parents could track their infant’s growth measurements (weight, length) during the first two years and correlate these with maternal blood sugar levels from pregnancy, helping identify patterns in how pregnancy metabolism influences early growth.
This article describes a research protocol for an ongoing study; actual results are not yet available. The GROWTH Study is designed to investigate associations between maternal blood sugar and breast milk composition, but causation cannot be determined from observational data. This information is for educational purposes and should not replace personalized medical advice from your healthcare provider. Pregnant women should discuss blood sugar screening and management with their obstetrician, and parents should consult pediatricians about infant growth and nutrition. Individual responses to pregnancy metabolism and breastfeeding vary significantly, and this research will apply most directly to women who breastfeed.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.