Micronutrient Requirements


Although deficiencies of any required nutrients during fetal development can result in health problems for the child during his or her lifetime, several nutrients are of particular importance because maternal inade- quacies during pregnancy may contributing to devastating birth defects. Terefore, in addition to helping pregnant athletes achieve a balanced dietary intake, encouraging the use of multivitamins or prenatal vita- mins is key to ensuring a healthy first trimester.


IRON


While hemoglobin mass does not significantly expand until the second and third trimesters of pregnan- cy, increased dietary intake of iron is recommended from the time of conception to accommodate normal iron losses, support fetal and placental growth, and build iron stores before demands become more pro- nounced.140


prepregnancy values.141


Te current RDA for iron during pregnancy is 27 mg/d, representing a 50% increase from Female athletes may be at elevated risk for iron deficiency and iron-deficiency ane-


mia due to heightened levels of hepcidin, a peptide hormone that inhibits iron absorption and sequesters iron in the macrophage. Research indicates that hepcidin concentrations increase in response to exercise, which makes early screening of added importance to this population.142


Not only can iron deficiency and


iron deficiency anemia exacerbate feelings of fatigue and compromise overall maternal health in the first trimester, but they can also contribute to poor pregnancy outcomes, including preterm delivery, prema- turity, and small for gestational age birth weight.140,143


In some cases, iron deficiency may escalate risk for


pica, the act of craving substances (oſten non–food related) like ice, dirt, and clay, that contain little to no nutritional value. Tis behavior can be harmful for both mother and child, especially when the cravings in- clude nonfood substances that increase the risk of exposure to toxic and parasitic ingredients. Tere also seems to be a correlation between iron deficiency and restless leg syndrome, making inclusion of questions regarding history of restless leg syndrome and pica of possible benefit when screening for deficiency.144


In


addition to incorporating iron-rich foods, such as lean meat, seafood, edamame, white beans, nuts, forti- fied grain products, and spinach, supplemental iron is recommended if ferritin levels drop below 70 μg/L. Suggested supplement guidelines are as follows143


:


• Ferritin greater than 70 μg/L: no iron supplements • Ferritin 31 to 70 μg/L: 30 to 40 mg ferrous iron per day • Ferritin 30 to 15 μg/L: 60 to 80 mg ferrous iron per day • Ferritin less than 15 μg/L and/or iron-deficiency anemia: therapeutic doses of 100 mg ferrous iron per day


FOLATE


Folate plays an integral role in the transformation of the neural tube into the brain and spinal cord during the first 28 days of pregnancy and provides consequent protection against neural tube defects like spina bifida and anencephaly. Folate requirements increase from preconception values of 200 mcg/d to 600 mcg/d during the first trimester.145,146


Continued supplementation with 400 mcg/d in the second and third trimesters has


been shown to increase maternal and cord blood folate status and prevent the increase in homocysteine concentration that otherwise occurs in late pregnancy; thus, supplementation may be of added benefit to pregnancy outcomes, and health in early childhood.147


Ensuring adequate dietary consumption from such


natural food sources as avocados, oranges, asparagus, green leafy vegetables, dried beans, and peas, as well as fortified grain products, should serve as the first line of defense. However, over-the-counter supplemental folate is oſten needed to achieve red blood cell folate levels associated with maximal protection against neu- ral defect, especially when maternal nutrition is compromised secondary to morning sickness, a common first-trimester symptom.146


Multivitamin tablets with folate are generally found in three formats:


• Regular over-the-counter multivitamins with 400 mcg to 600 mcg folate • Prenatal over-the-counter multivitamins with 1,000 mcg folate • Prescription multivitamins with 5,000 mcg folate


368 SECTION 3: PRINCIPLES IN PRACTICE


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