Good Nutrition Linked to Better Sleep During Pregnancy

A prospective analysis of the nuMoM2b Sleep substudy was published in Current Developments in Nutrition: The higher the quality of the diet in pregnancy (as measured by the HEI-2005), the longer and better their sleep. The association remained after controlling for multiple factors. The study does not prove causation, but it adds weight to the “pregnancy plate” advice: more whole foods, vegetables, fruits, whole grains, fish, and dairy; less added sugar and ultra-processed foods.

Background

• Sleep is often disrupted during pregnancy, and it is not harmless. Insomnia, snoring/OSA, and sleep fragmentation increase during pregnancy; the disturbances are associated with an increased risk of hypertensive disorders, gestational diabetes, and other adverse outcomes.
• Diet and sleep interact in both directions, but data specifically for pregnancy are scarce. Reviews emphasize that despite the obvious clinical significance, there are few high-quality prospective studies on the relationship between diet quality and sleep in pregnant women - this is the current gap.
• The HEI is a recognized way to assess the "quality" of a diet. The Healthy Eating Index summarizes the diet's compliance with nutritional recommendations (0-100 points); the 2005 version of the HEI uses component counts by food group/nutrient.
• nuMoM2b is a large US cohort studying first-time pregnancy outcomes. The main sample includes ≈10,000 primiparous women; a dedicated nuMoM2b Sleep substudy has conducted objective sleep measurements (home breathing studies, questionnaires, actigraphy) and follow-up in thousands of participants. This infrastructure allows testing whether diet quality predicts sleep characteristics.
• What the new work covers. A prospective analysis in Current Developments in Nutrition tested whether high HEI-2005 is associated with sleep duration and quality during pregnancy, accounting for multiple confounding factors - filling the gap between disparate data on nutrition and sleep parameters in pregnant women.
• Practical context: If a "healthy" diet is confirmed to be associated with better sleep, this provides a safe, non-pharmacological intervention to reduce risks (GDM, hypertension) where both sleep and diet are modifiable factors.

What exactly did they do?

• They took participants from the American cohort nuMoM2b Sleep (Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be), where sleep in pregnant women is measured and monitored prospectively.
• The quality of nutrition was assessed using the Healthy Eating Index (HEI-2005) - a total score showing how close the diet is to healthy eating recommendations.
• Main outcomes: sleep duration and quality during pregnancy; statistical models adjusted for potential confounding factors (age, BMI, etc.).

What did they find?

• Higher HEI = better sleep. Participants with higher diet quality had longer nights and better sleep quality scores. This is consistent with previous evidence linking “healthy” dietary patterns (DASH/Mediterranean) to better sleep overall and in pregnancy.
• The results fit into a picture where sleep and nutrition are linked in a two-way relationship: poor sleep worsens food choices, and a good diet helps stabilize sleep rhythms, blood sugar, and inflammatory processes that are important in gestation.

Why is this important?

• During pregnancy, sleep is shorter and worse, and this is associated with unfavorable outcomes (GDM, excessive weight gain, cesarean section, etc.). Any safe, non-drug methods to improve sleep are worth their weight in gold, and nutrition seems to be one of the levers here.
• The work adds prospective data: first assessing diet, then sleep. This is stronger than simple "slices" and closer to the reality of everyday recommendations.

How does this compare to previous research?

• Large reviews and meta-analyses show that better diet quality is associated with better sleep outcomes (less disruption, adequate duration). Similar signals have been found for pregnant women in Asia and Europe; the new study extends the findings to a larger American cohort.

Restrictions

• Observational study: improving HEI does not automatically "cure sleep." There may be residual confounding factors and reverse causality (better sleepers are better able to eat healthier).
• Assessment of both diet and some sleep parameters relies on questionnaires; this is better than nothing, but always less accurate than, say, actigraphy/polysomnography.

What can be done today

• Collect HEI points "the easy way": half a plate - vegetables/fruits, a quarter - whole grains, a quarter - protein (fish, legumes, poultry), plus dairy/fermented milk. Limit added sugar and ultra-processed foods.
• Maintain a sleep routine: regular hours, moderate dinner 2-3 hours before bed, caffeine before lunch. These behavioral steps go hand in hand with a “healthy plate” and potentiate the effect. (The link between poor sleep and obstetric risks is another incentive to pay attention to this.)
• All changes are in consultation with a doctor, taking into account toxicosis, anemia, gestational diabetes mellitus and other pregnancy features.

Source: Kahe K. et al. "Diet Quality and Sleep During Pregnancy - A Prospective Study in the nuMoM2b Sleep Cohort", Current Developments in Nutrition, May 2025 (open access). DOI: 10.1016/j.cdnut.2025.106150