Home> Nutrition > Prenatal Vitamins               

Prenatal Vitamins

If you are pregnant or breast feeding your doctor may recommend prenatal vitamins to supplement your diet. Prenatal vitamins are intended to provide the additional 30 mg per day of iron required by women during pregnancy in order to prevent iron deficiency anemia [1] .  In addition prenatal vitamins should contain 400 to 800 micrograms of folic acid to decrease the chances of the  birth defects spina bifida (open spinal cord)  and anencephaly (absence of a major portion of the skull and brain)  which occur during the first six weeks of pregnancy[2]

Beyond  Iron and Folic Acid

Whether or not supplements, such as docosahexaenoic acid (DHA), given to all pregnant and breast feeding women improves pregnancy outcome or development in their infants is unsettled [3-7] . However,  for some women supplements may be a good idea. For example, additional vitamin B12 might benefit strict vegetarians and women with a history of gastric bypass, since they are at risk for vitamin B12 deficiency due to low intake and poor absorption respectively [8]. Women with low calcium intake might decrease their chances of developing preeclampsia by taking calcium supplements , in addition to their prenatal vitamins,  during pregnancy [9]. Although vitamin D deficiency is a common problem for most pregnant women,  first time mothers, African-American women, and Hispanic women appear to be at highest risk for vitamin D deficiency and could benefit from additional vitamin D in their diet or as a supplement. [22]. Women who are unable to obtain enough iodine from their diet through dairy products, iodized salt, or fish might benefit from an iodine supplement {23-25]. Lastly additional choline might help to decrease the chances of the birth defects spina bifida and  anencephaly even in women already receiving extra folate in their diet [26].


For twin pregnancies it is recommended that during the first trimester women take one multivitamin tablet with iron (30 mg) daily. Additional folic acid 1,000 mcg, calcium 1,500 mg , vitamin D 1,000 IU, magnesium 400 mg, vitamin C 750 mg, and vitamin E 400 IU should be provided daily if not provided by their multivitamin.

During the second and third trimesters  women with twin pregnancies should take two multivitamin tablets with iron (30 mg) tablets daily. Calcium intake should be increased to 2,500 mg per day and magnesium intake should be increased to 800mg. Folic acid,  vitamin D, vitamin C, and vitamin E  should be continued at the same amounts as for the first trimester [27].

See Also:
Nutrition in Twin Pregnancy

Choice of Prenatal Vitamins

The choice of prenatal vitamin will often depend on patient acceptance and cost. Prenatal vitamins may worsen nausea, abdominal discomfort, and constipation that are common during pregnancy. Women who are having severe nausea and vomiting in early pregnancy may need to temporarily stop taking their prenatal vitamins, or use a vitamin with decreased or no iron content until their condition improves.  Intake of iron-rich foods should be encouraged. Some dietary sources of iron include beef,  turkey, duck, clams, chicken, soybeans, fortified cereals, lentils, spinach, lima beans, refried beans, chickpeas, tomatoes, and prune juice [10-13].

Some women who have trouble swallowing pills have been known to replace their prenatal vitamin with chewable FlintstonesTM vitamins. However, as shown in the table below FlintstonesTM vitamins provide only one half the amount of iron and folic acid as do other prenatal vitamins. It would be necessary to take two FlintstonesTM vitamins to meet the daily recommended amounts for iron and folic acid  [21]. Although taking two FlintstonesTM vitamins would provide more than the recommended daily intake of vitamin A and several other nutrients, the amounts of vitamin A and other nutrients would still be considered to be safe for the mother and fetus [18-20].

On occasion, the additional cost of a name brand prenatal vitamin may be justified if the brand named version causes less stomach upset, has a more acceptable taste,  or is easier to swallow . Otherwise, where cost is a concern reputable generic versions of the more popular brands can provide substantial savings [14-21].

Table 1. Comparison Of the Content of Some Vitamins Commonly Taken During Pregnancy

Nutrient units FlintstonesTM
Nature Made® Multi Prenatal Stuart
DRI * Pregnancy
19 to 50 years
Vitamin A
(as Beta-Carotene)
 mcg RAE
 150 (1000)  375 (2500) 600 (4000) 600 (4000) 770


Vitamin A 600 (2000) 300 (1000)    
Vitamin E IU (mg) 30 (30) 30 (30) 11 (11) 30 (30) 15 (15)
Vitamin C mg 60 85 100 120 85
Folic Acid mcg 400 1000  800 800 600
Vitamin B1
mg 1.5  1.4 1.5 1.8 1.4
Vitamin B2  
mg 1.7 1.4 1.7 1.7 1.4
Niacin mg 15 18  18 20 18
Vitamin B6
mg 2 1.9 2.6 2.6 1.9
Vitamin B12 (cyanocobalamin) mcg 6  2.6  4  8 2.6
Vitamin D  (cholecalciferol) IU (mcg) 400 (10) 400 (10) 400 (10) 400 (10) 200 (5)
Biotin mcg 40 30  30
Choline mg 38 450
Pantothenic Acid mg 10 6 6
Calcium mg 100 250 250 200 1000
Iodine mcg 150 220 220
Magnesium mg 20 50 360
Iron mg 18  27  27 28  27
Copper mcg 2000 1000 1000
Zinc mg 12 7.5 25 25 11
Chromium mcg 30 30
Manganese mg 2 2
Molybdenum mcg 50 50
Selenium mcg 30 60

*DRI= Daily Reference Intake;  3.33 IU Vitamin A = 1 mcg RAE  ; 6.66 IU beta carotene from supplement = 1mcg RAE


1.  Recommendations to prevent and control iron deficiency in the United States. Centers for Disease Control and Prevention. MMWR Recomm Rep 1998;47(RR-3):1–29.PMID:9563847
2. U.S. Preventive Services Task Force.Folic acid for the prevention of neural tube defects: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2009 May 5;150(9):626-31.PMID:19414842
3.Shah PS, Ohlsson A; Knowledge Synthesis Group on Determinants of Low Birth Weight and Preterm Births. Effects of prenatal multimicronutrient supplementation on pregnancy outcomes: a meta-analysis. CMAJ. 2009 Jun 9;180(12):E99-108. PMID:19506270
4.Haider BA, Bhutta ZA.Multiple-micronutrient supplementation for women during pregnancy.Cochrane Database Syst Rev. 2006 Oct 18;(4):CD004905.PMID:17054223
5. Rumbold A, Middleton P, Crowther CA.Vitamin supplementation for preventing miscarriage.Cochrane Database Syst Rev. 2005 Apr 18;(2):CD004073. PMID:15846697
6.Jensen CL, et al. Effects of Early Maternal Docosahexaenoic Acid Intake on Neuropsychological Status and Visual Acuity at Five Years of Age of Breast-Fed Term Infants. J Pediatr. 2010 Jul 22. PMID:20655543
7. Gale CR, Marriott LD, Martyn CN, Limond J, Inskip HM, Godfrey KM, Law CM, Cooper C, West C, Robinson SM; Group for the Southampton Women's Survey Study. Breastfeeding, the use of docosahexaenoic acid-fortified formulas in infancy and neuropsychological function in childhood.Arch Dis Child. 2010 Mar;95(3):174-9. Epub 2010 Feb 4.PMID:20133326
8. Andrès E, Federici L, Affenberger S, Vidal-Alaball J, Loukili NH, Zimmer J, et al. B12 deficiency: a look beyond pernicious anemia. J Fam Pract 2007;56:537-42.PMID:17605945
9. Hofmeyr GJ, Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems. Cochrane Database Syst Rev. 2010 Aug 4;8:CD001059.PMID:20687064
10. Nguyen P,et al Predictors of prenatal multivitamin adherence in pregnant women.J Clin Pharmacol. 2009 Jun;49(6):735-42. Epub 2009 Apr 22.PMID:19386624
11. Gill SK, et al. The effectiveness of discontinuing iron-containing prenatal multivitamins on reducing the severity of nausea and vomiting of pregnancy. J Obstet Gynaecol. 2009 Jan;29(1):13-6. PMID:19280488  
12. Zhou SJ, Gibson RA, Crowther CA, Makrides M. Should we lower the dose of iron when treating anaemia in pregnancy? A randomized dose-response trial. Eur J Clin Nutr. 2007 Oct 10. PMID: PMID:17928802
13. Souza AI, et al.Adherence and side effects of three ferrous sulfate treatment regimens on anemic pregnant women in clinical trials..Cad Saude Publica. 2009 Jun;25(6):1225-33. PMID:19503953
14.Product label Flintstones Complete.  Bayer HealthCare LLC.http://www.flintstonesvitamins.com/complete/index.html#ingredients
15.Materna product label http://www.materna.ca/About/Default.asp
16.Product label Stuart Prenatal http://www.naturemade.com/ProductDatabase/prd_prod.asp?productid=182
17. Product label http://www.stuartprenatal.com/preconception_formula.html
18. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc (2001)  Food and Nutrition Board (FNB) Institute of Medicine (IOM)2001
19. Dietary Reference Intakes for Calcium, Phosphorous, Magnesium, Vitamin D, and Fluoride (1997); http://www.nap.edu/catalog.php?record_id=5776
20. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic
Acid, Biotin, and Choline (1998); Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids (2000); http://www.nap.edu/catalog.php?record_id=6015
21. National Academy of Sciences

22. Johnson DD, et al. Vitamin D Deficiency and Insufficiency is Common during Pregnancy.Am J Perinatol. 2010 Jul 16. PMID:20640974
23. Gallego G, et al. Iodine deficiency in Australia: is iodine supplementation for pregnant and lactating women warranted?
Med J Aust. 2010 Apr 19;192(8):461-3.PMID:20402611
24. Limbert E, et al. Iodine intake in Portuguese pregnant women. Results of a countrywide study.Eur J Endocrinol. 2010 Jul 19. PMID:20643757
25. Perrine CG, et al. Some subgroups of reproductive age women in the United States may be at risk for iodine deficiency.
J Nutr. 2010 Aug;140(8):1489-94. PMID:20554903
26. Shaw GM, et al. Choline and risk of neural tube defects in a folate-fortified population. Epidemiology. 2009 Sep;20(5):714-9. PMID:19593156
27. Goodnight W, et al. Optimal nutrition for improved twin pregnancy outcome. Obstet Gynecol. 2009 Nov;114(5):1121-34. PMID: 20168116

Home | About | Disclaimer | Privacy | Contact

Copyright © 2013-4 by Focus Information Technology. All rights reserved.