Supplementation and pregnancy

Pregnancy involves an increase in energy needs due to the physical, physiological and biochemical changes of the state. This increase in the energy needs of the mother is due to the fact that during the pregnancy period the metabolic demands that the embryo and fetus entail must be satisfied. In addition, during pregnancy, the accumulation of reserves necessary for the lactation period should be guaranteed 1 .

In general, and if there is no type of pathology, both before, during and after pregnancy, most of the vitamin and mineral needs are covered with a varied and balanced diet. However, vitamin supplements  can help meet the increased requirements of certain nutrients in different situations.

The role of folic acid during pregnancy

A vitamin that is recommended in all cases is folic acid. Vitamin B9 or folic acid is found naturally in food, specifically in dark green leafy vegetables such as spinach, broccoli, chard, asparagus … etc.

According to the latest healthy eating guide 2 of the Spanish Society of Community Nutrition, it  is necessary for all pregnant women or those who are thinking of becoming pregnant an extra intake of folic acid of 400 µg daily, especially before conception, at least 1- 2 months 3 , to avoid malformations at the level of the neural tube in the fetus. In the case of being a woman with a history of neural tube defects, women who have had a previous child with a neural tube defect, diabetics or patients who are taking anti-convulsants, supplementation is stricter, and a daily dose of 5mg is recommended. of folic acid .

Are other supplements necessary during pregnancy?

In case of mineral or vitamin deficiency, the doctor or nutritionist will determine the need or not for other supplements. Some of the minerals most likely to be deficient are iron, iodine, or calcium.


The most common cause of anemia during pregnancy is due to a lack of iron, since the requirements are increased during pregnancy 3 .  For this reason, it is important that different blood tests are carried out throughout the pregnancy. However, there is insufficient evidence to recommend routine iron supplementation in women who do not suffer from anemia 1 .

The cases in which supplementation is recommended are:

  • Inadequate intake of the mineral from the diet.
  • Multiple pregnancies
  • Maternal iron deficiency during pregnancy.
  • Utero-placental hemorrhages.


A severe and moderate iodine deficiency during pregnancy and lactation affects the thyroid function of the mother and the neonate, as well as the neuropsychological development of the child.

Different studies carried out in Spain confirm that the majority of women in the pregnancy or lactation stage have an iodine 1 deficiency . The use of iodized salt is recommended in the general population and the consumption of white and blue fish, in order to prevent a possible iodine deficit during pregnancy 4 .

Iodine supplementation during pregnancy and lactation should be selective, not population-based, and should only be prescribed to women at high risk of insufficient iodine intake or of developing thyroid dysfunction in these stages 1 .


In the case of calcium, an extra supply of this mineral is necessary, since the fetus captures 200-250 mg per day during the third trimester of pregnancy. The main sources of calcium in food are found in milk, yogurt and cheese, which is why a daily consumption of 3-4 servings is recommended in pregnant women and 4-6 servings in lactating women 2 .

There are no trials to prove that calcium supplements during pregnancy offer any benefit to the bone health of the mother or fetus. On the other hand, they will be recommended only in pregnant women at risk to reduce the incidence of hypertension and preeclampsia 1 or in people whose daily calcium intake is not enough to cover the increased needs during the pregnancy and lactation period.

On the market there are nutritional supplements that may be necessary in different situations during pregnancy, but it is important to bear in mind that their supplementation must be prescribed with the scientific criteria of a doctor and / or nutritionist.


  1. Martínez Suárez V, Dalmau Serra J, Moreno Villares JM. Pediatrician and nutritional recommendations during pregnancy and lactation. Acta Pediatr Esp . 2015.
  2. Dapcich V, Salvador G, Ribas L, Pérez C, Aranceta J, Serra L. Guide to healthy eating. Senc  2004: 105.
  3. Puerperium G of work of G of clinical practice of care in pregnancy and. Clinical practice guide for care in pregnancy and the puerperium. Clinical Practice Guidelines in the SNSAETSA 2011/10 . 2014.
  4. General Directorate of Public Health of Asturias. Recommendations about iodine nutrition in the preconception stage, pregnancy and lactation. 2015.

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