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Why Is Maternal Supplementation Important?

A pregnant person holding a pill in one hand and a glass of water in the other.
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Undernutrition during pregnancy can lead to both short- and long-term effects on infant and maternal health, impacting development, increasing the risk of certain diseases and affecting the survival rate for both mother and child. It can be challenging for mothers to consume the necessary vitamins and minerals needed throughout pregnancy – including vitamin D, folate, calcium, iron and omega-3 fatty acids – from food alone, and oftentimes supplementation is required.

In this article, we explore the latest research on maternal diet and supplementation, and the effect they can have on pregnancy and childhood development.

Optimizing the intake of key nutrients in pregnancy

Researchers from NIH’s Environmental Influences on Child Health Outcomes (ECHO) Program explored what low-calorie foods might boost nutrient intake, much like dietary supplements do.

In a new study published in The Journal of Nutrition, the scientists found that no single food evaluated could provide sufficient intake of six key nutrients in a reasonable serving size. However, several readily available foods could help to boost the intake of single nutrients such as vitamin A (0.2 cups of raw carrot) and vitamin D (2.6 cups of reduced-fat milk).


“Results highlight the difficulty in meeting nutritional requirements from diet alone and imply that dietary supplements are likely necessary to meet vitamin D and iron targets in pregnancy, as well as omega-3 fatty acid targets for individuals who do not consume fish products,” the authors say.

A diet high in omega 3 and folate associated with reduced miscarriage risk

Omega 3 fatty acids and folic acid support human health in a variety of ways. Omega 3 provides structure to all human cell membranes and plays important roles in both the cardiovascular and endocrine systems. Folic acid – the synthesized version of folate – is essential for cell division and supports the body in creating DNA and RNA. The American Heart Association (AHA) recommends a diet high in fish, whole grains, omega-3 fatty acids and folic acid during pregnancy.

Researchers – led by the Food, Nutrition, Development and Mental Health research group of the University of Rovira i Virgili (URV) – had previously found that adherence to a diet rich in folic acid, vitamin B12, vitamin D, low-pesticide fruits and vegetables, whole grains, seafood, dairy and soy foods was associated with a higher likelihood of a live birth following infertility treatment with assisted reproductive technologies (ART).

In a more recent study published in JAMA Network Open, the researchers used data from a sample of 612 women aged 18–45 who underwent infertility treatments to investigate the effects of different diets on the gestational health of women.

They analyzed the diet of the women and their partners before they started ART and the extent to which the women followed one of the eight selected dietary patterns using food frequency questionnaires. They discovered that those who most followed the pattern recommended by the AHA for cardiovascular prevention were 13–15% less likely to miscarry than those who did not.

“The study has confirmed that regularly ingesting these nutrients and foods is associated with a lower risk of suffering a miscarriage during assisted reproduction cycles, so they are essential for human reproduction," points out lead author Dr. Albert Salas-Huetos, lecturer at the URV’s Preventive Medicine Unit and principal researcher at the Biomedical Research Centre (Cyber) of the Carlos III Institute and the Pere Virgili Health Research Institute.

Prenatal vitamin D can reduce the risk of infant asthma and wheezing

Vitamin D is important for general human health, aiding with the regulation of calcium, magnesium and phosphate absorption in the body.

During pregnancy, low levels of vitamin D are associated with an abundance of long-term effects for mother and infant. "Vitamin D deficiency is very common, especially in pregnant women who are not taking supplements," says Dr. Scott T Weiss, professor of medicine at Harvard Medical School. Weiss is the lead author of a recent review on prenatal vitamin D supplementation and childhood asthma, published in The Journal of Allergy and Clinical Immunology.

The review provides 15 years’ worth of data from the Vitamin D Antenatal Asthma Reduction Trial (VDAART), a randomized, double-blind and placebo-controlled trial that launched in 2014. After adjusting for baseline levels of vitamin D, the researchers found that maternal vitamin D supplementation (4,400 IU/d) reduced the rates of asthma and wheezing by 50% in children aged 3 and 6 years, compared to a standard prenatal multivitamin and a placebo.

“Based on our findings, we would recommend that all pregnant women consider a daily intake of at least 4400 IU vitamin D3 throughout their pregnancy, starting at the time of conception,” Weiss says.

Low fiber intake during pregnancy is linked to neurodevelopmental delays

Dietary fiber is a type of carbohydrate that is found in plant-based foods and aids healthy digestion. Unlike other carbohydrates it cannot be fully broken down by the digestive enzymes in the human digestive system.

Dietary fiber is also incredibly important during pregnancy. Previous studies in animals have shown a high-fiber diet during pregnancy is linked to improved immune system development, decreased risk of metabolic syndrome and decreased cognitive and social dysfunction caused by maternal obesity in offspring.

In Frontiers in Nutrition researchers explored the relationship between maternal nutritional imbalance and infants’ brain development at the age of 3 in ~76,000 mother–infant pairs from the Japan Environment and Children’s Study.

Participants were given food frequency questionnaires that asked about their dietary status during the second and third trimesters of pregnancy. Developmental delays were also assessed in a follow-up questionnaire that was sent to parents once their children were three years old.

The researchers discovered several delays in neurodevelopmental skills in infants associated with a lack of maternal dietary fiber. The children of mothers in the low-intake groups displayed problems with communication skills, problem-solving skills and personal–social skills compared to those in the high-intake groups. They also found delays in the development of large body part movement and coordination, as well as in the coordination of smaller muscles.

Although this study does highlight the importance of maternal diet for healthy infant development, “the possibility of other nutrients having an impact cannot be completely ruled out,” lead author Dr. Kunio Miyake, a researcher at the University of Yamanashi points out. “In addition, dietary fiber intake from supplements could not be investigated.”

The importance of maternal supplementation

The impact of maternal nutrition on infant health is undeniable and the complexity of achieving optimal nutrient intake through food alone highlights the importance of maternal supplementation.