What supplements should I take before pregnancy and why?

Supplements to Start Pre-Pregnancy

All women planning pregnancy should take a daily folic acid supplement of 400 μg (0.4 mg) starting at least 1-3 months before conception and continuing through the first trimester to reduce the risk of neural tube defects. 1

Folic Acid: The Essential Pre-Pregnancy Supplement

• Daily folic acid supplementation of 400 μg (0.4 mg) is recommended for all women of childbearing age who could become pregnant 1
• Begin supplementation at least 1-3 months before conception and continue through the first 12 weeks of pregnancy 1
• Folic acid significantly reduces the risk of neural tube defects (NTDs) by 40-80% 1, 2
• Women can obtain folic acid through supplements, multivitamins, or fortified foods 1
• Recent evidence shows that folic acid supplementation before pregnancy decreases the odds of neural tube defects (OR = 0.56) 2

Higher Dose Recommendations for High-Risk Women

• Women with higher risk factors should take 4 mg (4000 μg) of folic acid daily starting at least 3 months before conception through the first 12 weeks of pregnancy 1
• High-risk factors include: 1
  • Personal history of a previous NTD-affected pregnancy
  • First-degree relative with an NTD
  • Being personally affected by an NTD
  • Partner with personal history of NTD
• Women with type 2 diabetes or BMI >30 kg/m² should take 5 mg folic acid daily until the 12th week of pregnancy 1

Safety Considerations with Folic Acid

• Total daily folic acid intake should not exceed 1 mg (1000 μg) unless prescribed by a physician 1
• Higher doses may potentially mask vitamin B12 deficiency, which could lead to irreversible neurological damage if left untreated 1, 3
• Folic acid is water-soluble and excess is rapidly excreted in urine 1
• When taking higher doses of folic acid (>1 mg), check vitamin B12 status before starting 1, 3

Other Important Pre-Pregnancy Supplements

Vitamin B12

• Consider vitamin B12 supplementation, especially for vegetarian women 4
• Vitamin B12 deficiency may cause reduced fetal growth 4
• A multivitamin containing at least 2.6 μg/day of vitamin B12 is recommended alongside folic acid 5

Iron

• Iron supplementation may be beneficial for low-income women or those in developing countries 4
• Maternal iron deficiency can impact neonatal iron stores and birth weight 4
• Iron deficiency may cause cognitive and behavioral problems in childhood 4

Calcium

• Calcium supplementation is not necessary for women with adequate dietary intake (3 dairy servings/day) 6
• Consider supplementation for women with inadequate intake or at high risk of preeclampsia 4, 6

Vitamin D

• Vitamin D supplementation in the third trimester may be beneficial for vitamin D deficient women 4
• Deficiency is associated with adverse pregnancy outcomes 4

Practical Considerations

• Since more than 50% of pregnancies are unplanned, continuous folic acid supplementation is recommended for all women of childbearing age 1
• A prenatal multivitamin containing folic acid can help ensure adequate intake of multiple essential nutrients 5
• Poor compliance with folic acid recommendations is common due to: 7
  • Busy lifestyles
  • Competing priorities
  • Poor memory for daily supplementation
  • Skepticism about necessity
• Women should be educated about the severity of neural tube defects and the evidence for risk reduction 7
• Starting supplements before pregnancy is more effective than beginning after conception 2

Cautions

• Avoid excessive vitamin A supplementation during pregnancy as it may cause birth defects; upper limit for retinol supplements is 3000 IU/day 4
• Vitamin E supplementation is not recommended as it may disrupt physiologic oxidative gestational state 4
• Excessive zinc supplementation may interfere with copper absorption 1