Diet Quality in Pregnancy and the Risk of Fetal Growth Restriction

While a fetus is developing within a mother’s womb, it’s possible for his/her growth to be stunted (or “restricted”) due to a number of factors, including the mom’s health and genetic abnormalities.

Fetal growth restriction (FGR) is a condition in which an unborn baby is smaller than expected based on the point in pregnancy. Although not always, long-term effects of fetal growth restriction can sometimes include abnormal development of organs, tissues and cells that affect the fetus’s ability to breathe, fight off infections and more.

What causes fetal growth restriction? New research suggests there’s a link between fetal growth restriction and diet quality in some cases. In other words, it’s important for a pregnant mom to eat a nutrient-rich pregnancy diet because this provides the essential “building blocks” that help grow and develop a healthy baby.

Study Findings: Healthy Diet Can Lower Risk of Fetal Growth Restriction

A 2022 study published in the American Journal of Obstetrics and Gynecology investigated the link between maternal malnutrition and negative, long-term pediatric outcomes. Specifically, the study focused on the hypothesis that a high-quality diet during pregnancy is associated with a lower risk of fetal growth restriction.

How are fetal growth restrictions diagnosed? In the study, which included 762 pregnant mothers in their third trimester of pregnancy, fetal growth restriction was defined as fetal weight less than 10th percentile at time of delivery. In other words, newborns who are smaller than 90% of other newborns at the time of birth are thought to have experienced fetal growth restrictions.

In addition to looking at fetal size, the study also investigated secondary outcomes during pregnancy, including hypertensive/high blood pressure disorders of pregnancy (such as preeclampsia), large for gestational age and gestational diabetes.

The 2015 Healthy Eating Index (HEI), a tool developed by the U.S. Department of Agriculture, was used to assess the quality of pregnant mothers’ diets. HEI is based on 13 nutritional components and assigns a score between 1 and 100. A high HEI score equates to a healthier diet, while a lower HEI score equates to a less healthy diet.

Results of the study showed that:

• 17% of pregnant moms had a high HEI score, while 83% had a lower HEI score. The average score was 60 out of 100.
• Patients with a high HEI score were 67% less likely to experience fetal growth restriction.
• Those with high HEI scores were also 54% less likely to have hypertension during pregnancy compared to those with lower HEI scores.
• There was no differences found between low and high HEI groups related to large for gestational age or gestational diabetes.

In conclusion, the study uncovered an association between fetal growth restriction and diet quality, mainly that a high-quality diet is associated with decreased risk of FGR and hypertensive disorders during pregnancy.

What It Means

Researchers involved in the study believe that HEI scores may be a useful tool for identifying those at higher risk for pregnancy complications.

Having a high HEI score means that someone scores well on 13 nutritional components that are used to assess the quality of people’s diets. You can think of a high HEI score as an anti-inflammatory diet similar to the Mediterranean diet.

High intake of the food groups below is associated with a higher HEI score and linked to healthier pregnancy outcomes:

• Vegetables
• Whole fruits
• Greens
• Beans/legumes
• Whole grains
• Healthy fats from sources such as nuts, seeds, avocado, olive oil, fish and eggs
• Moderate intake of dairy and total protein

On the other hand, too much added sugar, sugary drinks, trans fats and refined grains are associated with lower HEI scores and should be avoided.

Pregnancy Diet Tips

It’s well-known that a high-quality diet can contribute to better pregnancy outcomes, as well as fetal health and development. Here are tips for eating a nutrient-rich diet while pregnant:

• Don’t overconsume calories in general, since too much weight gain and obesity during pregnancy are linked to poorer health for both mom and baby. On average, pregnant women need about 300 to 500 more calories per day (more toward the end of pregnancy).
• Include plenty of quality protein foods in your diet from healthy sources, such as eggs, beans, legumes, nuts, seeds and fish like salmon.
• Make sure you consume enough folate, calcium, iron, zinc, and vitamin D, which are all important nutrients for developing babies. Get these nutrients from foods including green veggies, lean meats, whole grains, sweet potatoes, dairy products such as yogurt or kefir, dried fruits, seeds, and nuts such as almonds and walnuts.
• It can also be beneficial to supplement with vitamin D and get some sunlight exposure each day if possible.
• Eat at least five or more servings of high-antioxidant fruits and vegetables each day, especially things like leafy greens, asparagus, oranges, berries, peppers and other colorful plants.
• Avoid raw meat, unpasteurized dairy and raw fish, which can contain bacteria linked to foodborne illnesses.
• Reduce intake of processed meats, deli meats and seafood/fish that contain high levels of mercury, such as swordfish, king mackerel and shark.

How else do you fix fetal growth restrictions?

Here are risk factors for FGR that should be avoided or treated with help from a health care provider:

• Smoking, using drugs or alcohol consumption during pregnancy.
• Mom being obese.
• Mom having high blood pressure, other forms of cardiovascular disease or diabetes.
• Mom experiencing anemia, lung or kidney conditions, or an autoimmune disease.
• Mom having an untreated infection.

Can fetal growth restrictions improve?

In some cases, yes. It’s usually recommend that pregnant women experiencing FGR keep up with regular and early prenatal care, eat a healthy diet and maintain healthy/steady weight gain, and cut out other risk factors, like smoking and drinking alcohol.

Sometimes the use of corticosteroid medications, early delivery or emergency cesarean sections are also needed to prevent complications.

Conclusion

• A new study demonstrated that fetal growth restriction causes can include a pregnant mother eating a poor diet, meaning one lacking nutrient-dense foods like veggies, fruit, whole grains, eggs, fish, nuts and seeds.
• Because outcomes of fetal growth restriction can include abnormal development of tissues and organs, a healthy diet during pregnancy is highly recommended to reduce the risk for fetal complications, in addition to issues like hypertension during pregnancy.
• If you’re pregnant, limit consumption of added sugar, refined grains and processed foods made with trans fats and additives. Try to avoid gaining too much weight, becoming obese before getting pregnant, or having high blood or diabetes pressure before pregnancy, which can lead to poor outcomes.