Nutritional Supplementation in Pregnancy

Introduction

Pregnancy, typically lasts 37-40 weeks, is a critical period of rapid foetal growth and development as well as maternal physiological change.

• Nutrient requirements are increased to provide for the optimal growth and development of the foetus and to support maternal health.
• An additional of 340 to 450 kcal/day for pregnant women in second or third trimester.

Lifestyle Modifications

When treating pregnant patients, lifestyle modifications should always be considered first.

• Avoid alcohol and other known or potentially harmful substances (e.g. smoking, illicit drug and mercury)
• Avoid fish containing high levels of mercury (shark, billfish, tuna, swordfish).
• Limit caffeine intake to less than 200-300 mg per day.
• Be mindful of other forms of caffeine in black tea, coke, energy drinks and gym supplements.
• Teratogenic drugs should be discontinued prior to pregnancy, if possible.

Preconception Care with Folic Acid

Folic acid is recommended in all women of childbearing age. It is important in preventing neural tube defects, such as spina bifida and anencephaly, which occurs during the early stages of pregnancy and also aids in red blood cell formation.

• Folic acid 400-500 mcg daily for at least 4 weeks prior to pregnancy and for the first 12 weeks of gestation.
• Folate requirements increase to 600 mcg daily on the fourth to ninth of pregnancy.

NOTE: A higher dose of folic acid (5 mg daily until 12 weeks of gestation) is recommended for high-risk women (e.g. previous history of neural tube defects, anticonvulsant medication, gestational diabetes mellitus).

Calcium and Vitamin D Supplementation

The baby's skeleton requires adequate calcium and vitamin D. If deficient in calcium, the mother's bone health will be sacrificed to provide for the baby.

• Maintain adequate intake of calcium (total of 1000-1300 mg elemental calcium per day).
• Apart from foetal bone development, calcium supplementation during pregnancy, especially for women with low dietary calcium intake, may reduce the incidence of hypertensive disorders (including pre-eclampsia) and preterm labour.
• Maintain adequate vitamin D intake (around 600 IU or 15 mcg)
• Reduces risk of pre-eclampsia, pre-term birth, small-for-gestational-age birth and gestational diabetes.
• Do not take cod liver oil or any supplements containing vitamin A (retinol).

Iron Supplementation

Iron is required for foetal brain growth and development and prevention of anaemia.

• Maintain adequate intake of iron (about 27 mg of iron per day).
• Supplementation is recommended for those with established deficiency and those at risk of deficiency (including vegetarians, women with a multiples).

Although iron supplementation can worsen morning sickness, women with iron-deficiency anaemia should not stop taking iron supplements without consulting a doctor.

Iodine Supplementation

Iodine is essential for production of maternal thyroid hormone, foetal brain and CNS development.

• Maintain adequate iodine intake (250 mcg).

External Links

• UpToDate - Nutrition in pregnancy: Dietary requirements and supplements
  
• NHS UK - Vitamins, supplements and nutrition in pregnancy
  
• ACOG - Nutrition During Pregnancy
  
• Blackmore Institute - Condition Information Sheet
  
• Omega-3 Fatty Acids and Pregnancy, 2010
  
• Iodine intake in pregnancy—even a little excess is too much, 2015
  
• Safety and efficacy of supplements in pregnancy, 2020
  
• Vitamin D supplementation and incident preeclampsia: A systematic review and meta-analysis of randomized clinical trials, 2019