Q&A: Assessing, addressing poor diet quality during pregnancy

Key takeaways:

• Lower education, lower income and high BMI are risk factors for low diet quality during pregnancy.
• More research is needed examining the association between diet quality and the prenatal microbiome.

Some social determinants of health act as barriers to maintaining a healthy diet during pregnancy and higher saturated fats and added sugar may be tied to the composition and function of the prenatal microbiome.

“If we can understand how to deliver appropriate, tailored messaging to women about what they are eating ... it will make a huge impact in their lives,” Anna Maria Siega-Riz, MS, PhD, dean of the School of Public Health and Health Sciences and professor in the departments of nutrition, biostatistics and epidemiology at the University of Massachusetts Amherst, told Healio. “We can do blood work and examine the microbiome during pregnancy, but interpreting all of this information to provide tailored nutrition advice is still an area that needs further exploration.”

In a study published in The American Journal of Clinical Nutrition evaluating diet quality during early pregnancy through 1 year postpartum, Siega-Riz and colleagues observed that adherence to dietary guidelines were consistent throughout pregnancy and postpartum, but having a low diet quality was common among all women.

Using the same cohort of pregnant women, Siega-Riz and colleagues further observed that specific dietary components were associated with microbial composition and function during the second trimester. This study was recently published in The Journal of Nutrition.

Healio spoke with Siega-Riz about these two studies, including nutrients that might impact the microbiome during pregnancy, and how clinicians can help pregnant women maintain a healthy diet.

Healio: Could you explain the design of the Pregnancy Eating Attributes Study?

Siega-Riz: We were interested in understanding what the motivators and barriers were for women eating healthy during pregnancy and how it was associated with gestational weight gain over the course of pregnancy. The Pregnancy Eating Attributes Study is a cohort study, meaning that we enrolled women early on in pregnancy, less than 12 weeks’ gestation, and followed them through pregnancy and the postpartum period. We are now following the kids through the ages of 6 and 7 years. The reason why that study design is so important is it allows you to measure behaviors and look at outcomes later, so it’s the appropriate temporality to be able to say that something can be associated with something else, but it’s not causal. It’s not a randomized trial, so you can’t say this is causing that.

Healio: Few studies have analyzed diet quality during pregnancy and postpartum in the same participants. Why was it important to do this?

Siega-Riz: We collected multiple 24-hour recalls over the course of pregnancy and postpartum. That allowed us to pick up more of the types of foods that women were eating compared with a food frequency questionnaire. The reason why it was important to do this is because there is a lot of literature that says pregnancy is a time where women are motivated to make changes so that they can eat healthier. While that motivation is true, if they’re not living in an environment that is supportive, or if they don’t necessarily have the income to afford healthier eating, they don’t make changes. And that is exactly what we observed.

Healio: What does the study suggest are risk factors for low diet quality?

Siega-Riz: What we find during pregnancy is not dissimilar to what we’re finding in the general population. Compared with the general population, pregnant women have a slightly higher Healthy Eating Index score of 61 than the general population, which is about 58 (on a scale of 0 to 100). The risk factors for low diet quality are lower education, lower income and having a higher BMI. Those social determinants of health, education and income, influence what you’re eating. That’s what led us to reemphasize and put our study in context with all the other studies that say that if we want people, pregnant or not, to eat healthy, they need to live in a supportive environment. They need to be in an environment that predominantly provides healthy foods. They need to be in an environment that encourages meal planning and allows women to have the time to be able to eat. It also means that we have to have a health care system that values and supports healthy eating, so that when women go in and see their provider, whether it’s a nurse practitioner, midwife or clinician, they are reinforcing healthy eating patterns so women can take care of themselves and then learn how to take care of their infants and children as they begin to learn how to eat foods at the table and develop their own eating patterns over time.

Healio: How can OB/GYNs assess pregnant patients to see if they are at risk for food insecurity or if they need help maintaining a healthy diet?

Siega-Riz: Right now, everybody needs help maintaining a healthy diet. The problem is a lot of OB/GYNs don’t have time. If we can increase their awareness of the fact that they need to be able to refer pregnant women to nutritionists or dietitians in the community or in the clinics that they work in, that those professionals can then spend the time that is needed to assess food insecurity. You assess food insecurity by using some basic validated questions available from the U.S. Department of Agriculture. If you find someone is food insecure, then you want to make sure that you’re connecting them to services in their community to be able to alleviate that food insecurity. You want to make sure they’re participating in the Women, Infants and Children (WIC) supplemental program. You want to make sure that they are eligible and receive the Supplemental Nutrition Assistance Program (SNAP) benefits. There are food bank resources in communities, and some health care programs have insurance coverage for extra nutrition services for pregnant women, even allowing for medically tailored meals delivered to their homes. The more that clinicians are aware of these types of services, the greater likelihood that they can refer their patients and follow up to make sure that they’re connecting to these services.

Healio: In a related study, you and colleagues performed a genomic analysis of the gastrointestinal microbiome during the second trimester and you found an association between higher saturated fats and added sugar and the composition and function of the prenatal microbiome. What research is needed to understand these results?
Siega-Riz: We need to be able to duplicate our research in multiple populations to make sure that we’re seeing similar findings. We followed a paper that was published in BMJ Gut, which included a general population, not a pregnant population, and also included people with gastrointestinal problems, like irritable bowel syndrome. We used their methodology for assessing these relationships with the diversity of the microbiome, but also the functionality of those particular microbiomes, and that is what helped us understand these relationships between the particular foods and the function of that particular microbiome. We are the first ones to do that in a pregnant population. We need to conduct other studies that can replicate those findings. We only used a fecal swab, which was a quick and easy way of being able to assess the microbiome in the gut. Repeated samples over the course of pregnancy would help to validate the findings that we have here.

For more information:

Anna Maria Siega-Riz, MS, PhD, can be reached at asiegariz@umass.edu; Instagram: @UMasssphhs.

References:

• Bolte LA, et al. BMJ Gut. 2021;doi:10.1136/gutjnl.2020.322670.
• Dreisbach C, et al. J Nutr. 2024;doi:10.1016/j.tjnut.2024.09.016.
• Lipsky LM, et al. Am J Clin Nutr. 2024;doi:10.1016/j.ajcnut.2024.09.016.
• Food Security in the U.S. – Survey Tools. Published Jan. 8, 2025. Accessed Jan. 23, 2025. https://www.ers.usda.gov/topics/food-nutrition-assistance/food-security-in-the-us/survey-tools.