Essential Supplements During Pregnancy
All pregnant women should take a daily multivitamin and mineral supplement containing folic acid, iron, calcium, vitamin D, and other essential micronutrients throughout pregnancy to support maternal health and optimal fetal development. 1
Core Recommended Supplements
Folic Acid
- Standard recommendation: 0.4 mg daily during preconception and first trimester 1
- Higher dose (4-5 mg daily) recommended for women with BMI >30 kg/m² or diabetes 1, 2
- Prevents neural tube defects, orofacial clefts, cardiac anomalies, and may reduce risk of anemia, spontaneous abortions, pre-eclampsia, IUGR, and placental abruption 3
- Pregestational supplementation is critical for neural tube defect prevention 3
Iron
- Recommended dose: 45-60 mg elemental iron daily (>18 mg for women with adjustable gastric banding) 1, 2
- Low-dose iron (30 mg/day) often recommended during second and third trimesters 1
- Prevents iron deficiency anemia, which directly impacts neonatal iron stores and birth weight 3
- Iron deficiency may cause cognitive and behavioral problems in childhood 3
- Supplementation particularly important for low-income pregnant women and in developing countries 3
Calcium
- Recommended intake: 1200-1500 mg daily in divided doses (includes dietary intake) 1, 2
- WHO strongly recommends calcium supplementation (1.0-1.5 g/day) to prevent preeclampsia, particularly in populations with low dietary calcium intake 2
- Should be administered in divided doses of not >500 mg elemental calcium per dose 2
- May reduce both the risk of low birth weight and severity of pre-eclampsia 3
Vitamin D
- Recommended supplementation: >40 mcg (1000 IU) daily 1, 2
- Should maintain serum concentration of at least 50 nmol/L 1, 2
- Supplementation in vitamin D-deficient women during third trimester appears beneficial 3
- Safety in excess of 400 IU daily during pregnancy has not been established according to some sources 4
Additional Important Supplements
Vitamin B12
- Recommended dose: 1 mg daily (oral) or 1 mg every 3 months (intramuscular) 2
- Particularly important for vegetarian women 3
- Insufficient supply may cause reduced fetal growth 3
Other Essential Micronutrients
- Thiamine: >12 mg daily 1, 2
- Copper: 2 mg daily (>1 mg for women with adjustable gastric banding) 1, 2
- Zinc: 8-15 mg per 1 mg copper 1, 2
- Vitamin K: 90-120 μg daily 1, 2
- Vitamin E: 15 mg daily 1, 2
- Vitamin A: 5000 IU daily (should be in beta-carotene form during pregnancy) 1, 2
- Selenium: 50 μg daily 1, 2
Monitoring During Pregnancy
- Serum folate, vitamin B12, ferritin, iron studies, and full blood count should be checked at least once per trimester 1
- Serum vitamin D with calcium, phosphate, magnesium, and parathyroid hormone should be monitored at least once per trimester 1
- More frequent monitoring recommended for women with history of bariatric surgery 1, 2
Special Considerations and Pitfalls
Supplement Interactions
- Calcium can inhibit iron absorption, but clinical studies show minimal effects 2
- For simplicity and adherence, providers should not insist that calcium and iron pills be taken separately 2
- Mineral oil interferes with absorption of fat-soluble vitamins, including vitamin D 4
Vitamin A Caution
- The retinol form of vitamin A should be avoided during pregnancy due to teratogenicity risk; beta-carotene form is preferred 1, 2
- Upper limit for retinol supplements is 3000 IU/day 3
Supplement Availability
- Almost no US dietary supplements provide key nutrients in the doses needed for pregnant women 5
- Most prenatal supplements do not contain optimal doses of all recommended nutrients 5
Women with Bariatric Surgery
- Require more intensive monitoring and supplementation 1, 2
- Monthly ultrasound monitoring of fetal growth recommended due to increased risk of fetal growth restriction 1
- More frequent nutritional screening during each trimester is recommended 1
- Women should avoid pregnancy for 12-18 months following bariatric surgery 1