Prenatal vitamins are specially formulated supplements designed to fill nutritional gaps during pregnancy and, ideally, in the months before conception. Even a well-balanced diet can fall short of the increased nutrient demands of pregnancy, making prenatal vitamins an important part of prenatal care.
Ideally, you should begin taking prenatal vitamins at least one month before trying to conceive — and continue throughout pregnancy and breastfeeding. The neural tube, which develops into the baby's brain and spinal cord, closes within the first 28 days of pregnancy, often before many women know they are pregnant. Adequate folic acid in the weeks before and after conception is critical for preventing neural tube defects such as spina bifida.
Folic acid (folate): 400–800 mcg — The most critical nutrient in early pregnancy. Women with a personal or family history of neural tube defects may be advised to take a higher dose (4 mg). Look for methylfolate if you have the MTHFR gene variant, as it is the more bioavailable form.
Iron: 27 mg — Your blood volume nearly doubles during pregnancy, and iron supports the production of haemoglobin. Iron deficiency anaemia is common in pregnancy and can cause fatigue, preterm birth, and low birth weight. Take iron with vitamin C to enhance absorption, and avoid taking it with calcium-rich foods or supplements, which inhibit uptake.
Calcium: 1,000 mg (1,300 mg if under 19) — Supports bone and teeth development in the baby. If your prenatal vitamin does not contain enough calcium, a separate supplement may be recommended. Note that prenatal vitamins rarely contain the full daily requirement, as calcium competes with iron for absorption.
Vitamin D: 600 IU (many experts recommend 1,000–2,000 IU) — Works with calcium to build the baby's bones and teeth. Vitamin D deficiency is very common in pregnancy, particularly in regions with limited sunlight, and has been linked to gestational diabetes and preeclampsia.
Omega-3 DHA: 200–300 mg — An essential fatty acid that supports fetal brain and eye development. Many prenatal vitamins do not include DHA; a separate fish oil or algae-based supplement may be needed, especially if you do not eat oily fish regularly.
Iodine: 220 mcg — Essential for fetal thyroid development and cognitive function. Iodine deficiency is one of the most common preventable causes of intellectual disability worldwide.
Vitamin B12 — Works alongside folic acid in cell division. Particularly important for women who follow a vegan or vegetarian diet, as B12 is found primarily in animal products.
Not all prenatal vitamins are equal. When comparing products, check that the supplement contains at least 400 mcg folic acid, 27 mg iron, and DHA. Third-party tested products (look for certifications from NSF, USP, or ConsumerLab) are independently verified for purity and potency.
If nausea makes swallowing tablets difficult, gummy vitamins are an alternative — but check the label carefully, as many gummies contain little or no iron. Taking your prenatal vitamin with a small snack or before bed can also help reduce nausea.
Prescription prenatal vitamins are regulated as drugs and must meet strict quality standards, but over-the-counter options can be equally good if carefully chosen. Your healthcare provider may recommend a prescription prenatal if you have specific nutritional needs, such as a higher iron requirement due to anaemia or a higher folate dose due to a history of neural tube defects.
Supplements complement a healthy diet — they do not replace it. Continue to eat a varied diet rich in fruits, vegetables, whole grains, lean protein, and dairy or fortified alternatives. Foods provide thousands of beneficial compounds that no supplement can fully replicate.
Speak with your healthcare provider before starting any new supplement during pregnancy. Use our Due Date Calculator to track your pregnancy timeline, or our Pregnancy Week Calculator for week-by-week guidance.
This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider regarding your specific situation.