Results from a Geisel School of Medicine study investigating whether following a planetary health style diet during pregnancy affects preterm birth and babies’ size at birth are published in the American Journal of Clinical Nutrition, “Adherence to the EAT-Lancet Planetary Health Diet during Pregnancy and Associations with Preterm Birth and Infant Size: a prospective analysis from the New Hampshire Birth Cohort.”
This is one of the first studies to specifically evaluate the planetary diet in pregnancy—a unique period with higher nutrient needs.
The paper’s lead author, Leyre Notario Barandiaran, MPH, PhD, a postdoctoral researcher in epidemiology working with Margaret Karagas, PhD, chair and James W. Squires Professor of Epidemiology and community and family medicine, says they examined whether adherence to the EAT-Lancet Planetary Health Diet—a dietary pattern designed to promote both human and planetary health—during pregnancy influences newborn outcomes. Its benefits for chronic disease prevention are recognized, but its impacts on birth outcomes were unclear.
Notario-Barandiaran, using data from over a thousand mothers and their infants in the New Hampshire Birth Cohort Study observed favorable associations. Mothers who more closely followed the Planetary Health Diet had babies with healthier birth weights, longer gestational duration (gestational age), and lower risk of preterm birth.
“We applied a machine-learning approach, Self-Organizing Maps, or SOMs, to identify real-world dietary patterns in the cohort,” she says. “This advanced method allowed us to uncover which food combinations are linked to the best and worst outcomes, offering clearer insights for future dietary recommendations.
“Three distinct dietary patterns were recognized within our cohort: a ‘plant-based’ pattern, a ‘saturated fat-rich’ pattern, and an ‘animal and added sugar-rich’ pattern. The latter two patterns were associated with poorer outcomes, including lower birth weight and a higher risk of preterm birth, when compared to the plant-based pattern,” Notario-Barandiaran adds.
There have been concerns that the Planetary Health Diet, because it limits animal-source foods, might not be nutritionally adequate to meet the increased demands of pregnancy. Rather than supporting that concern, the findings suggest that, in this cohort, greater adherence to this plant-forward pattern was linked to improved perinatal outcomes, particularly a slightly longer pregnancy and lower odds of preterm birth and a reduced risk of preterm birth.
“Because the EAT-Lancet framework explicitly integrates human health goals with environmental sustainability, this study provides evidence that a diet designed to benefit the planet can also support a healthy pregnancy, a critical window for long-term health,” she says.
The study results not only support a sustainable diet for a critical life stage like pregnancy but also opens the door for new public health recommendations that can benefit mothers, their babies, and the environment simultaneously.