Prenatal Nutrition

Anri Pretorius

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April 1, 2021
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The prenatal period defines the time between conception and birth. Prenatal nutrition is of the utmost importance as it falls within the First 1000 Days. The first 1000 days of an infant starts on the day conception took place and lasts until the baby is about two years old. This period is critical to ensure adequate nutrition for both the mother and the infant so that the infant can grow optimally and start with a good quality of life.14 

In this blog, I will talk about nutrition for the pregnant mother and mention the essential nutrients that the mother has to take into consideration. 

Nutrient requirements during pregnancy:

  1. Energy: Additional energy is required for the optimal growth of the fetus. Metabolism increases with an average of 15% during a singleton pregnancy but with wide variability, especially in the third trimester. Modifying energy intakes to make sure the pregnant woman gains appropriate weight is more important than calculating specific caloric requirements. 
    1. Exercise: The American College of Obstetricians and Gynecologists (ACOG) recommends at least 20 – 30 minutes of moderate intensity exercise for pregnant women on most days of the week.1 Pregnant women should always discuss exercise with their health care practitioner.
  1. Protein: The protein requirements of a pregnant woman are the same during the first half of pregnancy, but the intake increases as weight gain is obtained. The RDA (recommended daily allowance) in the second half of pregnancy increases to 1,1g/kg/day. Protein deficiency during pregnancy has adverse consequences like poor fetal growth. Special attention has to be paid to vegetarians, those pregnant with multiples, or women that are still growing themselves to ensure a proper protein intake. The WHO recommends that 23% of calorie requirements should come from protein in pregnant women.2 Supplementation, if necessary, should be with food sources rather than supplements. 
  1. Carbohydrates: Priority should be given to complex carbohydrates like whole grains, fruits and vegetables rather than simple and refined carbohydrates, including refined liquid sugars like fruit juices and sodas. 
  1. Fiber: A daily consumption of 28g of fiber is recommended.15 Fiber will help with any constipation issues during pregnancy. Sources include whole grain breads and cereals, green leafy vegetables and yellow vegetables, fresh and dried fruit which will all provide extra vitamins, minerals and fiber. 

Vitamins necessary during pregnancy:

  1. Folate: Low folate levels are associated with miscarriages, LBW (low birth weight) and preterm birth. Early maternal folate deficiency is associated with an increased incidence of orofacial clefts, congenital heart defects and NTDs (neural tube defects e.g. spinal bifida).4 Therefore, the CDC (Centers for Diseases Control and Prevention) recommends that all women of childbearing age have a daily intake of 400mcg folic acid. Folic acid/ folate can be found in supplements or fortified foods like breakfast cereals.5 Natural food sources that contain folate are your leafy green vegetables, broccoli and brussel sprouts.
  1. Vitamin B6/ Pyridoxine: Good sources include meat, fish and poultry and because these sources are quite common and because prenatal vitamins contain adequate amounts, deficiencies are not quite common. However, “a deficiency is associated with pre-eclampsia, gestational carbohydrate intolerance, hyperemesis gravidarum, and neurological disease of infants.” 6
  1. Vitamin B12/ Cobalamin: Important in growth, development and immune function. Vitamin B12 is primarily found in animal sources, so vegetarians and especially vegans are at risk of developing a dietary Vitamin B12 deficiency. They should consume fortified foods that contain Cobalamin or supplement it.7
  1. Choline: Needed for structural integrity of cell membranes, cell signaling and nerve impulse transmission. Choline and folate are metabolically interrelated, and both support fetal brain development and lowers the risk of NTDs.8 Choline-rich foods include milk, meat and egg yolks, and pregnant women not eating these food sources might need supplementation.
  1. Vitamin C: Daily consumption of good food sources are encouraged, like fruit and vegetables. During pregnancy, vitamin C is important for fetal growth and development of connective tissue.9 
  1. Vitamin A: Is critical during rapid growth periods and vital in cellular differentiation, ocular development, immune function, and lung maturity.9 Supplementation is often unnecessary and is usually limited to 3000 IU (international units)/ day.6 Dietary sources of vitamin A for pregnant women include yellow and orange fruits and vegetables.
  1. Vitamin D: Requirements do not increase during pregnancy and an intake of 600 IU/day are sufficient when considering bone health. The few dietary sources of Vitamin D are salmon and other fatty fish and fortified foods like breakfast cereals.10 Vitamin D can also be obtained through exposure to sunlight.
  1. Vitamin K: Sources include dark green leafy vegetables. Vitamin K has a vital role in coagulation homeostasis, preventing the risk of maternal hemorrhage. 9

Minerals necessary during pregnancy:

  1. Calcium: Has a role in bone formation, and low calcium intake is associated with an increased risk of IUGR (intrauterine growth restriction) and preeclampsia (high blood pressure/ hypertension in pregnancy).6 Dietary products like milk and yogurt are the most common sources of dietary calcium.
  1. Copper: Copper deficiency alters embryo development.7 Good sources of copper include seafood, nuts, seeds and wholegrains. Because of the relatively large amounts consumed, potatoes, tea, milk and chicken are also important sources.11 
  1. Iodine: Because the thyroid hormone synthesis increases by 50% during pregnancy, iodine requirements also increase.12 Severe iodine deficiency is associated with increased risk for fetal goiter, miscarriage, stillbirth and decreased IQ. Fish and seafood are good sources of iodine as well as iodized table salt (<2300mg/day).
  1. Iron: The RDA for iron significantly increases in pregnancy.9 The best sources of iron are red meats, including wild meats because of the animal proteins high biological value (HBV). Vegetarian pregnant women should pay particularly close attention to their iron levels and supplement if necessary. 
  1. Sodium: The ACOG has previously recommended that sodium should not be restricted below 2300mg/day, which is higher than the current DRI.13 Iodized salt should be encouraged and processed foods discouraged because they tend to contain high, non-iodized salt.
  1. Zinc: Critical for growth and development, zinc requirements for the pregnant woman increases.6 Even a mild deficiency may lead to poor fetal development and growth and poor brain development and immune function.9 Zinc dietary sources are widely available and include red meat, seafood, wholegrains and some fortified breakfast cereals.
  1. Selenium: Functions as an antioxidant and is important for reproduction.  Low selenium levels are associated with recurrent miscarriages, IUGR and preeclampsia. The DRI increases slightly during pregnancy.6  Sources of selenium include brazil nuts, fish and chicken. 

It is important to remember that if pregnant women eat a well-balanced diet that has enough variety most of the vitamins and minerals’ DRIs (daily recommended intakes) will be met. Unnecessary supplementation is not recommended, and it’s important to  always consult with your health care practitioner before starting supplementation. 

Proper hydration and enough sleep are both also very important during pregnancy. Pregnant women need support from their partners, families and communities to help them nurture and care for the fetus and soon to be infant so that the fetus will grow optimally and feel loved. 

References:

  1. American College of Obstetricians and Gynaecologists: ACOG Committee Opinion No. 650: physical activity and exercise during pregnancy and the postpartum period, Obstet Gynecol 126:e135-e142, 2015a.
  2. Millward DJ: Identifying recommended dietary allowances for protein and amino acids: a critique of the 2007 WHO/FAO/UNU report, Br J Nutr 108(Suppl 2):S3-S21, 2012.
  3. Millward DJ: Identifying recommended dietary allowances for protein and amino acids: a critique of the 2007 WHO/FAO/UNU report, Br J Nutr 108(Suppl 2):S3-S21, 2012.
  4. Obeid R, Holzgreve W, Pietrzik K: Is 5-methyltetrahydrofolate an alternative to folic acid for the prevention of neural tube defects? J Perinat Med 41:469-483, 2013.
  5. Centers for Disease Control and Prevention: Folic acid, 2018a. Available at: https://www.cdc.gov/ncbddd/folicacid/index.html
  6. Hovdenak N, Haram K: Influence of mineral and vitamin supplements on pregnancy outcome, Eur J Obstet Gynecol Reprod Biol 164:127-132, 2012.
  7. Krause and Mahan’s ‘Food and the Nutrition Care Process’, chapter 14, 15th edition.
  8. Zeisel SH: Nutrition in pregnancy: the argument for including a source of choline, Int J Womens Health 5:193–199, 2013.
  9. Wu G, Imhoff-Kunsch B, Girard AW: Biological mechanisms for nutritional regulation of maternal health and fetal development, Paediatr Perinat Epidemiol 26:4–26, 2012a.
  10. Holick MF: The vitamin D deficiency pandemic: Approaches for diagnosis, treatment and prevention, Rev Endocr Metab Disord 18:153–165, 2017.
  11. Otten JJ, Hellwig JP, Meyers JD: Dietary reference intakes: the essential guide to nutrient requirements, Washington, DC, 2006, Institute of Medicine of the National Academies, National Academies Press.
  12. Stagnaro-Green A, Pearce E: Thyroid disorders in pregnancy, Nat Rev Endocri- nol 8:650–658, 2012.
  13. American College of Obstetricians and Gynecologists: Hypertension in Preg- nancy, November 2013, 2013c. Available at: Hypertension in Pregnancy (ilpqc.org)
  14. https://thousanddays.org/why-1000-days/
  15. Recommended Dietary Allowances and Intakes During Pregnancy (perinatology.com)

Edited by PreRD intern, Lauren Gatto

Anri Pretorius

Anri Pretorius

My name is Anri Pretorius, I am a South African citizen busy with my internship and final year of studies in dietetics. I am studying at the University of Stellenbosch. I love eating healthy foods and am particularly fond of spicy foods. I enjoy participating in any sport and see exercise as one of my favorite hobbies. The most recent sport I took up is cycling. I am a bibliophile and spend my vacations at home reading any book I can find that interests me. I also have two pets, a miniature french poodle and a rescue cat called Simba.