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Pregnancy nutrition: What PCPs need to know
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Adopting a nutritious, well-balanced diet prior to and during pregnancy can help promote healthy growth and development of the baby and improve maternal outcomes.
“A healthy diet assures adequate nutrients for both the mother and developing fetus,” Eva Pressman, MD, professor in the department of obstetrics and gynecology at the University of Rochester Medical Center, told Healio Primary Care Today.
“While the best way to deliver all nutrients is through a balanced diet, most pregnant women are prescribed a prenatal vitamin to ensure intake of the minimal amounts of a wide variety of recommended vitamins and minerals,” she added. “Deficiencies in a wide variety of vitamins and minerals are associated with poor health outcomes for both mother and infant.”
Healthy diet
While eating healthfully should be a lifelong goal, starting a balanced diet at least 3 months before conception will help ensure optimal nutrition in the first trimester of pregnancy, Pressman said. Additionally, starting healthy eating prior to pregnancy is best due to the associations between early pregnancy and nausea, vomiting and food aversions, she said.
Physicians should discuss diet with women during pregnancy to determine if any changes need to be made, Brietta M. Oaks, PhD, MPH, assistant professor in the department of nutrition and food sciences at the University of Rhode Island, told Healio Primary Care Today.
“Pregnancy is one of the time periods in life when people are open to changing their nutritional habits,” she said.
Physicians should advise pregnant women to avoid highly processed foods and consume more whole foods, such as fruits and vegetables, she said.
Essential nutrients
“The most important nutrients for fetal development are folic acid and iron, while the most important nutrients for maternal health are iron, calcium and vitamins C and E,” Pressman said.
For the infant, a folic acid deficiency may increase the risk for neural tube defects and an iron deficiency may delay brain development, according to Pressman.
Low iron stores will impair the normal dilutional anemia associated with pregnancy and increase the risk for complications associated with loss of blood in mothers, she said. Additionally, preeclampsia is more likely in mothers with calcium, vitamin C and E deficiencies, she said.
The ideal time to focus on iron and folic acid is prior to pregnancy, Oaks said.
Good sources of folic acid include dark green leafy vegetables, citrus fruits, whole grains and legumes, whereas good sources of iron include green leafy vegetables, whole grains and lean protein, according to the American Pregnancy Association.
The American Pregnancy Association recommends that pregnant women consume 600 µg to 800 µg of folic acid daily and 27 mg of iron daily.
Iron and folic acid supplements should be started if there is a concern that dietary intake of these nutrients is low, Oaks said.
“Many physicians and pregnant women are aware of the benefits of iron and folic acid for a healthy pregnancy,” Oaks said. “However, there are many other nutrients that are equally important during pregnancy and are often not discussed during pregnancy.”
Many prenatal vitamins do not contain magnesium despite the likelihood of many women not meeting the recommended intake of magnesium through diet alone, she said. Growing evidence suggests that magnesium may be linked to diabetes and there are an increasing number of women at risk for gestational diabetes during pregnancy, according to Oaks.
Additionally, choline is not often found in prenatal vitamins, but is important for brain development, she said. Foods such as eggs, soybeans and pork contain good amounts of choline. If these foods are not a regular part of a pregnant woman’s diet, she may have a higher risk for choline deficiency, she said.
Nutritional concerns
“Foods that pose an infectious risk to everyone are more concerning in pregnancy due to the potential for that infection to spread to the fetus,” Pressman said. “These include raw meat, fish, eggs and unpasteurized dairy products.”
“The main concern for these infections is Listeria,” she said.
Listeria has also been associated with deli meats, Hispanic-style cheeses, such as queso fresco, and soft cheeses, such as brie and feta, unless they are made with pasteurized milk, according to Pressman and Oaks.
“While Listeria causes mild illness in the pregnant women, it can have severe consequences for the fetus, including miscarriage, stillbirth and preterm birth,” Oaks said. “Pregnant women are actually 10 times more likely to get Listeria infection than the general population.”
Hispanic women who are pregnant have an even greater risk for Listeria infection, with a 24 times greater likelihood than the general population, she said.
Another dietary concern for pregnant women is mercury in certain fish, Pressman said.
“While eating fish is generally beneficial during pregnancy and the FDA recommends pregnant and breastfeeding women to eat up to 12 ounces of low-mercury fish a week, high mercury fish such as albacore tuna, swordfish and sea bass should be kept to a minimum since high levels of mercury can interfere with fetal brain development,” she said.
The effect of caffeine during pregnancy is uncertain because there has not been enough research, according to Oaks.
Studies that have been done on caffeine consumption during pregnancy have shown conflicting results, she said. Some studies have found that caffeine may increase the risk for miscarriage or low birth weight while others have not found these associations, she said.
“Current recommendations are that 200 mg of caffeine (approximately 12 ounces of coffee) appear safe,” Oaks said. “But it is worth considering some of the side effects of caffeine that occur regardless of if a person is pregnant, such as increasing BP or contributing to difficulty sleeping, and how important these are to a healthy pregnancy.”
Myths vs. reality
“Often pregnancy dietary myths are based on a kernel of truth that has been misunderstood or over simplified,” Oaks said.
For example, pregnant women are often told to “eat for two,” she said.
“This is based on the truth that pregnant women do need to eat more during pregnancy, but actually the increase in food is just needed in the second and third trimester,” she said. “Even then, the recommendation is typically 300 extra calories in the second trimester and 450 to 500 extra calories in the third trimester.”
It is important to note that these recommendations are meant for women entering pregnancy at a healthy weight, according to Oaks. Women entering pregnancy overweight or obese is becoming more and more common, and it is recommended that these women have a lower weight gain, she said. – by Alaina Tedesco
Disclosures: Oaks and Pressman report no relevant financial disclosures.