What supplement to take during pregnancy and how to choose a well-designed prenatal formula

Quick answer: what supplement to take during pregnancy

During pregnancy, the foundation of supplementation is a complete prenatal supplement, specifically formulated for this stage. It is not advisable to replace it with a set of isolated supplements without a holistic approach, because the nutrients needed during pregnancy act synergistically and your needs differ from those of the general population.

The Spanish Ministry of Health states that folate supplementation should start at least one or two months before conception, and that other micronutrients such as iodine need to be reviewed according to individual diet and context. The chemical form of each nutrient, its bioavailability, and the digestive tolerance of the formula determine whether the supplement actually fulfills its function or merely appears on the label.

A well-designed prenatal supplement should provide:

• Active folate (5-MTHF) or highly bioavailable folate

• Iron in a well-tolerated form (such as bisglycinate)

• Iodine for fetal thyroid and neurological development

• Vitamin D and B vitamins in active forms

• Choline, an essential nutrient frequently absent from generic formulas

• Zinc and other minerals in absorbable forms

Not all pregnant women need exactly the same regimen. Nutrients such as iron, vitamin D, or DHA may require adjustment based on blood tests, diet, and professional judgment.

Why prenatal supplementation matters even before pregnancy

Pregnancy creates an increased demand for micronutrients from the first weeks, many of them before the woman knows she is pregnant. The closure of the neural tube, for example, occurs between days 21 and 28 of gestation, a time when many pregnancies have not yet been confirmed. That is why Spanish clinical guidelines recommend starting folate supplementation at least one or two months before trying to conceive.

Diet remains the nutritional foundation, but available data on pregnant women in Spain indicate that adequate folate and choline intake through food is insufficient in most cases, falling far below 80% of the established recommendations. This is not a problem of poor nutrition, but rather that the physiological needs at this stage exceed what a regular diet can consistently cover.

What changes in the body during pregnancy and planning:

• Blood volume increases by up to 50%, which increases the need for iron and vitamins involved in red blood cell production.

• The development of the fetal nervous system requires folate, choline, iodine, and DHA from very early stages.

• The demand for vitamin D increases due to its role in fetal bone development and maternal immune function.

• Maternal thyroid metabolism intensifies, increasing iodine needs.

Starting supplementation before conception is not an excessive precaution: it is the way to enter pregnancy with the necessary nutrient stores already established.

Which nutrients are key in a pregnancy supplement

A complete prenatal is not limited to folic acid. The physiology of pregnancy involves elevated needs for several micronutrients simultaneously, and the quality of a formula depends as much on what it includes as on how it does so.

The following table summarizes the most relevant nutrients, their role in gestation, and what to look for on a supplement label:

Note on DHA: it is a relevant nutrient for fetal neurodevelopment, but not all prenatal formulas incorporate it. When it is not present, it can be considered as an additional supplement according to diet and professional judgment.

B vitamins: beyond folate

B vitamins form a group with interconnected functions. Riboflavin (B2) supports enzymatic energy metabolism, niacin (B3) participates in DNA synthesis and cell repair, and B1 (thiamine) is key for carbohydrate metabolism, especially relevant in the first trimester when nausea can compromise intake. A coherent prenatal formulation includes the complete B complex, not just folate and B12.

Active folate, iron bisglycinate, and choline: three criteria that make the difference

Within the nutrient profile of a prenatal, there are three elements that act as reliable indicators that the formulation has been designed with clinical judgment and not just the minimum required.

Active folate (5-MTHF) versus synthetic folic acid

Synthetic folic acid is the most common form in generic supplements, but it requires a chain of enzymatic conversions to become biologically active. The last step depends on the MTHFR enzyme, which presents frequent genetic variants: between 30 and 40% of the population may have a reduced conversion capacity. When folic acid exceeds that capacity, it accumulates in the blood as unmetabolized folic acid (UMFA), which is not biologically inert.

Active folate, on the other hand, is already in the form that the body uses directly. It does not depend on individual enzymatic efficiency and does not generate UMFA accumulation. Looking for it on the label as 5-MTHF, L-methylfolate, or Quatrefolic® is a concrete way to verify that the formula uses the bioavailable form.

Iron bisglycinate: digestive tolerance in the first trimester

First-trimester nausea and digestive sensitivity are frequent precisely when supplementation is most critical. Iron in the form of ferrous sulfate, present in most conventional prenatals, is known to cause constipation and gastric discomfort. Iron bisglycinate, being bound to glycine through a chelated bond, presents better absorption and significantly less irritation of the digestive mucosa.

Why it really matters: a supplement that causes discomfort tends to be abandoned. Digestive tolerance is not an aesthetic criterion: it is a direct factor of adherence, and adherence determines the real efficacy of supplementation.

Choline: the most forgotten nutrient in conventional prenatals

Choline is essential for fetal brain development, cell membrane synthesis, and placental function. Despite this, it is absent in most prenatal supplements on the market. A study published in Scielo on pregnant women in Spain found that adequate choline intake through diet was below 60% of the established recommendations. The EFSA establishes an adequate intake of 480 mg/day during pregnancy. Its presence in a prenatal formula indicates that the design has gone beyond the standard minimum.

Why many prenatal supplements fall short or are poorly formulated

The prenatal supplement market has a structural problem: the label does not always reflect the real quality of the formula. Two products with almost identical nutrient lists can behave very differently in the body depending on the chemical forms used, the actual doses, and the excipients included.

Frequent errors in generic formulations:

• Using synthetic folic acid as the sole source of folate, without considering individual enzymatic variability.

• Including iron as ferrous sulfate, which causes greater gastrointestinal irritation and worse adherence in the first trimester.

• Listing nutrients in symbolic doses, far below EFSA recommendations, simply to be able to include them on the label.

• Omitting choline, one of the nutrients with the greatest impact on fetal brain development.

• Using forms of vitamin B12 that require hepatic conversion (cyanocobalamin) instead of the active form (methylcobalamin).

• Including unnecessary excipients such as colorants, artificial flavors, or fillers that do not provide nutritional value.

Digestive tolerance is also a quality criterion. A formula that causes constant discomfort in the first trimester reduces adherence, and supplementation that is not taken continuously does not fulfill its function, regardless of how well formulated it is on paper.

How to choose a good prenatal supplement: practical checklist

To evaluate a prenatal supplement with judgment, the ingredients label is the most useful starting point. These are the concrete steps to distinguish a well-designed formula from a generic one:

1. Verify the form of folate. Look for 5-MTHF, L-methylfolate, or Quatrefolic® in the ingredients list. If only "folic acid" appears without further specification, the formula does not use the active form.

2. Check how the iron is formulated. Iron bisglycinate is the option with the best digestive tolerance profile. Ferrous sulfate is cheaper and more common, but also more irritating.

3. Look for whether it includes choline. Its presence, usually as L-choline bitartrate, indicates that the formula covers a critical nutrient that most prenatals omit.

4. Review the forms of B vitamins. Methylcobalamin (B12) and pyridoxal-5-phosphate (B6) are the active forms. Cyanocobalamin and pyridoxine require additional conversion.

5. Evaluate if DHA is included. If it is not, consider whether your diet covers it sufficiently or if a specific supplement may be necessary.

6. Read the excipients list. A quality formula does not need colorants, artificial flavors, or unjustified fillers.

7. Consider validity for all three stages. A prenatal designed to cover fertility, pregnancy, and lactation without changing products simplifies long-term adherence.

For a more detailed analysis of these criteria from a clinical point of view, you can consult the complete guide on how to choose a quality prenatal supplement.

Example of a well-designed formulation: what Prenatal 360 provides

Applying the above criteria to a specific formula helps to understand what the difference is in practice. Prenatal 360 by SANA Nutrients is an example of a prenatal that incorporates several of the elements described in this guide.

Criteria met by the formula according to its composition:

• Active folate: uses Quatrefolic® (L-5-methyltetrahydrofolate), the glucosamine salt of 5-MTHF, with direct bioavailability without the need for enzymatic conversion.

• Well-tolerated iron: includes iron in the form of bisglycinate, with a better absorption profile and less digestive irritation than conventional salts.

• Choline: present as L-choline bitartrate, covering a nutrient usually absent in generic prenatals.

• Active vitamin B12: in the form of methylcobalamin, directly usable by the body.

• Iodine and vitamin D3: present in the formula to cover two of the most prevalent needs during pregnancy in Spain.

• Complete B complex: includes B1, B2, B3 and B6, in addition to biotin.

• No unnecessary excipients: no colorings, synthetic flavors or unjustified fillers. Manufactured in Spain under GMP and ISO 9001 standards.

The formula does not include DHA in its current composition. If this nutrient is relevant to your case, it can be considered as an additional supplement. The SANA ingredients page details each component with formulation criteria and transparency.

Frequently asked questions about supplements during pregnancy

Which vitamins are essential during pregnancy?

Folate (in active form), iron, iodine and vitamin D are the nutrients with the greatest institutional support in Spain for supplementation during pregnancy. To these are added vitamin B12, choline and zinc as part of a complete prenatal formula. Exact needs vary depending on diet, lab tests and individual context.

Is nutrition during pregnancy sufficient?

Diet is the foundation, but data on pregnant women in Spain show that the adequacy of folate and choline through food is insufficient in most cases. Supplementation does not replace a balanced diet, but it does cover the deficiencies that the usual diet cannot consistently guarantee during this stage.

When should I start taking a prenatal supplement?

Ideally, at least one or two months before trying to conceive. The closure of the neural tube occurs in the first weeks of gestation, before many pregnancies are confirmed. Starting supplementation in the preconception stage allows you to enter pregnancy with folate and other nutrient stores already established.

What is the difference between folic acid and active folate?

Folic acid is the synthetic form of vitamin B9. To be usable, it needs to be converted into active folate (5-MTHF) through an enzymatic chain that does not work the same way in everyone. Active folate is already in the form that the body uses directly, without depending on that conversion. You can expand on this point in the clinical guide on prenatal supplements.

Are all prenatal supplements the same?

No. Two formulas with similar nutrient lists can differ significantly in bioavailability, digestive tolerance and formulation quality. The chemical form of each ingredient, the presence or absence of choline, and the use of active forms of B vitamins are differences that are not always visible on the front of the package but are in the ingredient list.

Do I need to take DHA separately?

DHA is an omega-3 fatty acid relevant to fetal neurodevelopment. Not all prenatal formulas include it. If the chosen prenatal does not provide it, it can be considered as an additional supplement depending on the usual consumption of oily fish and professional judgment.

How do I know if the iron in the prenatal makes me feel bad?

The most common symptoms of poor iron tolerance are constipation, nausea or gastric discomfort that coincide with the start of supplementation. Iron in the form of bisglycinate usually generates fewer of these effects than ferrous sulfate. If symptoms persist, it is advisable to check the chemical form of iron on the label and consider an alternative with better tolerance.