Learn More About Prenatal Vitamins
What is a prenatal vitamin supplement?
Prenatal vitamin supplementation refers to a precautionary intake of certain vitamins and minerals to ensure that the developing fetus receives an adequate supply of these vital components. Prenatal vitamins ensure that the mother has these nutrients and minerals available in case the diet does not supply them. Vitamin and mineral deficiencies can be linked to a variety of birth defects and complications.
What can be done to ensure a healthy pregnancy?
Enjoy a happy, healthy pregnancy. A healthy baby begins with a healthy mom, so start as soon as possible to prepare your body and mind for motherhood. According to research or other evidence, the following self-care steps may be helpful:
- Prenatal supplement
- Starting before you become pregnant, if possible, take a multivitamin supplement high in folic acid, iron, and calcium to prevent complications due to vitamin or mineral deficiencies
- Eat well
- A well-balanced and varied diet that includes fresh fruits and vegetables, whole grains, legumes, and fish will provide the nutrients you and your baby need
- Avoid harmful habits
- Give up alcohol, caffeine, smoking, and recreational drugs to reduce the risk of birth defects and pregnancy complications
- Gain the right amount of weight
- Follow the advice of your healthcare provider to prevent problems associated with inadequate or excessive weight gain
What evidence supports the use of prenatal vitamin supplements?
Most doctors, many other healthcare professionals, and the March of Dimes recommend that all women of childbearing age supplement with 400 mcg per day of folic acid. Such supplementation could protect against the formation of neural tube defects (such as spina bifida) during the time between conception and when pregnancy is discovered.
The requirement for the B vitamin folic acid doubles during pregnancy, to 800 mcg per day from all sources.27 Deficiencies of folic acid during pregnancy have been linked to low birth weight28 and to an increased incidence of neural tube defects (e.g., spina bifida) in infants. In one study, women who were at high risk of giving birth to babies with neural tube defects were able to lower their risk by 72% by taking folic acid supplements prior to and during pregnancy.29 Several preliminary studies have shown that a deficiency of folate in the blood may increase the risk of stunted growth of the fetus.30 31 32 33 34 35 36 37 This does not prove, however, that folic acid supplementation results in higher birth weights. Although some trials have found that folic acid and iron, when taken together, have improved birth weights,38 39 40 41 other trials have found supplementation with these nutrients to be ineffective.42 43 44
The relationship between folate status and the risk of miscarriage is also somewhat unclear. In some studies, women who have had habitual miscarriages were found to have elevated levels of homocysteine (a marker of folate deficiency).45 46 47 48 In a preliminary study, 22 women with recurrent miscarriages who had elevated levels of homocysteine were treated with 15 mg per day of folic acid and 750 mg per day of vitamin B6, prior to and throughout their next pregnancy. This treatment reduced homocysteine levels to normal and was associated with 20 successful pregnancies.49 It is not known whether supplementing with these vitamins would help prevent miscarriages in women with normal homocysteine levels. As the amounts of folic acid and vitamin B6 used in this study were extremely large and potentially toxic, this treatment should be used only with the supervision of a doctor.
In other studies, however, folate levels did not correlate with the incidence of habitual miscarriages.50 51 52
Preliminary53 and double-blind54 evidence has shown that women who use a multivitamin-mineral formula containing folic acid beginning three months before becoming pregnant and continuing through the first three months of pregnancy have a significantly lower risk of having babies with neural tube defects (e.g., spina bifida) and other congenital defects.
In addition to achieving significant protection against birth defects, women who take folic acid supplements during pregnancy have been reported to have fewer infections, and to give birth to babies with higher birth weights and better Apgar scores. 55 (An Apgar score is an evaluation of the well-being of a newborn, based on his or her color, crying, muscle tone, and other signs.) However, if a woman waits until after discovering her pregnancy to begin taking folic acid supplements, it will probably be too late to prevent a neural tube defect.
Biotin deficiency may occur in as many as 50% of pregnant women.56 As biotin deficiency in pregnant animals results in birth defects, it seems reasonable to use a prenatal multiple vitamin and mineral formula that contains biotin.
In a preliminary study, pregnant women who used a zinc containing nutritional supplement in the three months before and after conception had a 36% decreased chance of having a baby with a neural tube defect, and women who had the highest dietary zinc intake (but took no vitamin supplement) had a 30% decreased risk.57
Iron requirements increase during pregnancy, making iron deficiency in pregnancy quite common.58 Iron supplement use in the United States is estimated at 85% during pregnancy, with most women taking supplements three or more times per week for three months.59 Pregnant women with a documented iron deficiency need doctor-supervised treatment. In one study, 65% of women who were not given extra iron developed iron deficiency during pregnancy, compared with none who received an iron supplement.60 However, there is a clear increase in reported side effects with increasing supplement amounts of iron, especially iron sulfate.61 62 Supplementation with large amounts of iron has also been shown to reduce blood levels of zinc.63 Although the significance of that finding is not clear, low blood levels of zinc have been associated with an increased risk of complications in both the mother and fetus.64
Iron supplementation was associated in one study with an increased incidence of birth defects,65 possibly as a result of an iron-induced deficiency of zinc. Although additional research needs to be done, the evidence suggests that women who are supplementing with iron during pregnancy should also take a multivitamin-mineral formula that contains adequate amounts of zinc. To be on the safe side, pregnant women should discuss their supplement program with a doctor.
Supplementation with fish oil (providing either 2.7 g or 6.1 g per day of the omega-3 fatty acids EPA and DHA significantly reduced recurrence of premature delivery, according to data culled from six clinical trials involving women with a high risk for such complications.66 Fish oil supplementation did not prevent premature delivery of twin pregnancies, nor did it have any preventive effect against intrauterine growth retardation or pregnancy-induced hypertension. Fish oils should be free of contaminants, such as mercury and organochlorine pesticides. Women who eat substantial amounts of certain types of seafood (e.g., swordfish, tuna) may be consuming contaminants that can increase the risk of brain and nervous system abnormalities in their offspring. Exposure to mercury and polychlorinated biphenyls (PCBs) was found to be increased in relation to maternal intake of seafood. Higher exposure to these toxic contaminants has been linked to an increased risk of deficits in the developing brains and nervous systems of the children.67
SAMe (S-adenosylmethionine) supplementation has been shown to aid in the resolution of blocked bile flow (cholestasis), an occasional complication of pregnancy.68 69
Premature rupture of membranes (PROM) affects 10 to 20% of all pregnancies. It is an important cause of preterm delivery and is associated with increased rates of complications in both the mother and child. In a double-blind study, supplementing with 100 mg of vitamin C per day, beginning in the twentieth week of pregnancy, reduced the incidence of PROM by 74%.70 The women in this study were consuming only about 65 mg of vitamin C per day in their diet, which is less than the RDA of 80 to 85 mg per day for pregnant women.
Calcium needs double during pregnancy.71 Low dietary intake of this mineral is associated with increased risk of preeclampsia, a potentially dangerous (but preventable) condition characterized by high blood pressure and swelling. Supplementation with calcium may reduce the risk of pre-term delivery, which is often associated with preeclampsia. Calcium may reduce the risk of pregnancy-induced hypertension,72 though these effects are more likely to occur in women who are calcium deficient.73 74 Supplementation with up to 2 grams of calcium per day by pregnant women with low dietary calcium intake has been shown to improve the bone strength of the fetuses.75
Pregnant women should consume 1,500 mg of calcium per day from all sources—food plus supplements. Food sources of calcium include dairy products, dark green leafy vegetables, tofu, sardines (canned with edible bones), salmon (canned with edible bones), peas, and beans.
Copyright © Healthnotes, Inc. All rights reserved. www.healthnotes.com
This article was reprodced with permission from HealthNotes.com
27. Truswell AS. ABC of nutrition. Nutrition for pregnancy. Br Med J 1985;291: 263–6.
28. Scholl TO, Hediger ML, Schall JI, et al. Dietary and serum folate: their influence on the outcome of pregnancy. Am J Clin Nutr 1996;63:520–5.
29. MRC Vitamin Study Research Group. Prevention of neural tube defects: Results of the Medical Research Council Vitamin Study. Lancet 1991;338:131–7.
30. Tamura T, Goldenberg RL, Johnston KE, et al. Serum concentrations of zinc, folate, vitamins A and E, and proteins, and their relationships to pregnancy outcome. Acta Obstet Gynecol Scand Suppl 1997;165:63–70.
31. Tamura T, Goldenberg RL, Freeberg LE, et al. Maternal serum folate and zinc concentrations and their relationships to pregnancy outcome. Am J Clin Nutr 1992;56:365–70.
32. Goldenberg RL, Tamura T, Cliver SP, et al. Serum folate and fetal growth retardation: a matter of compliance? Obstet Gynecol 1992;795 (Pt 1):719–22.
33. Neggers YH, Goldenberg RL, Tamura T, et al. The relationship between maternal dietary intake and infant birthweight. Acta Obstet Gynecol Scand Suppl 1997;165:71–5.
34. Frelut ML, de Courcy GP, Christides JP, et al. Relationship between maternal folate status and foetal hypotrophy in a population with a good socio-economical level. Int J Vitam Nutr Res 1995;65:267–71.
35. Ek J. Plasma and red cell folate in mothers and infants in normal pregnancies. Relation to birth weight. Acta Obstet Gynecol Scand 1982;61:17–20.
36. Malinow MR, Rajkovic A, Duell PB, et al. The relationship between maternal and neonatal umbilical cord plasma homocyst(e)ine suggests a potential role for maternal homocyst(e)ine in fetal metabolism. Am J Obstet Gynecol 1998;178:228–33.
37. Burke G, Robinson K, Refsum H, et al. Intrauterine growth retardation, perinatal death, and maternal homocysteine levels. N Engl J Med 1992;326:69–70 [letter].
38. Iyengar L, Rajalakshmi K. Effect of folic acid supplement on birth weights of infants. Am J Obstet Gynecol 1975;122:332–6.
39. Rolschau J, Date J, Kristoffersen K. Folic acid supplement and intrauterine growth. Acta Obstet Gynecol Scand 1979;58:343–6.
40. Blot I, Papiernik E, Kaltwasser JP, et al. Influence of routine administration of folic acid and iron during pregnancy. Gynecol Obstet Invest 1981;12:294–304.
41. Baumslag N, Edelstein T, Metz J. Reduction of incidence of prematurity by folic acid supplementation in pregnancy. Br Med J 1970;1:16–7.
42. Fleming AF, Martin JD, Hahnel R, Westlake AJ. Effects of iron and folic acid antenatal supplements on maternal haematology and fetal wellbeing. Med J Aust 1974;2:429–36.
43. Fletcher J, Gurr A, Fellingham FR, et al. The value of folic acid supplements in pregnancy. J Obstet Gynaecol Br Commonw 1971;78:781–5.
44. Giles PF, Harcourt AG, Whiteside MG. The effect of prescribing folic acid during pregnancy on birth-weight and duration of pregnancy. A double-blind trial. Med J Aust 1971;2:17–21.
45. Sutterlin M, Bussen S, Ruppert D, Steck T. Serum levels of folate and cobalamin in women with recurrent spontaneous abortion. Hum Reprod 1997;12:2292–6.
46. Wouters MG, Boers GH, Blom HJ, et al. Hyperhomocysteinemia: a risk factor in women with unexplained recurrent early pregnancy loss. Fertil Steril 1993;60:820–5.
47. Steegers-Theunissen RP, Boers GH, Blom HJ, et al. Hyperhomocysteinaemia and recurrent spontaneous abortion or abruptio placentae. Lancet 1992;339:1122–3 [letter].
48. Quere I, Bellet H, Hoffet M, et al. A woman with five consecutive fetal deaths: case report and retrospective analysis of hyperhomocysteinemia prevalence in 100 consecutive women with recurrent miscarriages. Fertil Steril 1998;69:152–4.
49. Quere I, Mercier E, Bellet H, et al. Vitamin supplementation and pregnancy outcome in women with recurrent early pregnancy loss and hyperhomocysteinemia. Fertil Steril 2001;75:823–5.
50. Pietrzik K, Prinz R, Reusch K, et al. Folate status and pregnancy outcome. Ann N Y Acad Sci 1992;669:371–3.
51. Neiger R, Wise C, Contag SA, et al. First trimester bleeding and pregnancy outcome in gravidas with normal and low folate levels. Am J Perinatol 1993;10:460–2.
52. Neela J, Raman L. The relationship between maternal nutritional status and spontaneous abortion. Natl Med J India 1997;10:15–6.
53. Botto LD, Mulinare J, Erickson JD. Occurrence of congenital heart defects in relation to maternal mulitivitamin use. Am J Epidemiol 2000;151:878–84.
54. Czeizel AE. Reduction of urinary tract and cardiovascular defects by periconceptional multivitamin supplementation. Am J Med Genet 1996;62:179–83.
55. Tamura T, Goldenberg R, Freeberg L, et al. Maternal serum folate and zinc concentrations and their relationships to pregnancy outcome. Am J Clin Nutr 1992:56;365–70.
56. Mock DM, Quirk JG, Mock NI. Marginal biotin deficiency during normal pregnancy. Am J Clin Nutr 2002;75:295–9.
57. Velie EM, Block G, Shaw GM, et al. Maternal supplemental and dietary zinc intake and the occurrence of neural tube defects in California. Am J Epidemiol 1999;150:605–16.
58. Allen LH. Anemia and iron deficiency: effects on pregnancy outcome. Am J Clin Nutr 2000;71(5 Suppl):1280S–4S [review].
59. Yu SM, Keppel KG, Singh GK, Kessel W. Preconceptional and prenatal multivitamin-mineral supplement use in the 1988 National Maternal and Infant Health Survey. Am J Public Health 1996;86:240–2.
60. Romslo I, Haram K, Sagen N, Augensen K. Iron requirement in normal pregnancy as assessed by serum ferritin, serum transferrin saturation and erythrocyte protoporphyrin determinations. Br J Obstet Gynaecol 1983;90:101–7.
61. Hemminki E, Uski A, Koponen P, Rimpela U. Iron supplementation during pregnancy—experiences of a randomized trial relying on health service personnel. Control Clin Trials 1989;10:290–8.
62. al-Momen AK, al-Meshari A, al-Nuaim L, et al. Intravenous iron sucrose complex in the treatment of iron deficiency anemia during pregnancy. Eur J Obstet Gynecol Reprod Biol 1996;69:121–4.
63. Bloxam DL, Williams NR, Waskett RJD, et al. Maternal zinc during oral iron supplementation in pregnancy: a preliminary study. Clin Sci 1989;76:59–65.
64. Mukherjee MD, Sandstead HH, Ratnaparkhi MV, et al. Maternal zinc, iron, folic acid, and protein nutriture and outcome of human pregnancy. Am J Clin Nutr 1984;40:496–507.
65. Nelson MM, Forfar JO. Associations between drugs administered during pregnancy and congenital abnormalities of the fetus. Br Med J 1971;1:523–7.
66. Olsen SF, Secher NJ, Tabor A, et al. Randomised clinical trials of fish oil supplementation in high risk pregnancies. Fish Oil Trials In Pregnancy (FOTIP) Team. Brit J Obstet Gynecol 2000;107:382–95.
67. Steuerwald U, Weihe P, Jorgensen PJ, et al. Maternal seafood diet, methylmercury exposure, and neonatal neurologic function. J Pediatr 2000;136:599–605.
68. Frezza M, Centini G, Cammareri G, et al. S-adenosylmethionine for the treatment of intrahepatic cholestasis of pregnancy. Results of a controlled clinical trial. Hepatogastroenterology 1990;37 Suppl 2:122–5.
69. Frezza M, Surrenti C, Manzillo G, et al. Oral S-adenosylmethionine in the symptomatic treatment of intrahepatic cholestasis. A double-blind, placebo-controlled study. Gastroenterology 1990;99:211–5.
70. Casanueva E, Ripoll C, Tolentino M, et al. Vitamin C supplementation to prevent premature rupture of the chorioamniotic membranes: a randomized trial. Am J Clin Nutr 2005;81:859–63.
71. Truswell AS. ABC of nutrition. Nutrition for pregnancy. Br Med J 1985;291:263–6.
72. Villar J, Repke JT. Calcium supplementation during pregnancy may reduce preterm delivery in high-risk populations. Am J Obstet Gynecol 1990;163:1124–31.
73. Ritchie LD, King JC. Dietary calcium and pregnancy-induced hypertension: is there a relation? Am J Clin Nutr 2000;71(5 Suppl):1371S–4S [review].
74. Villar J, Belizan JM. Same nutrient, different hypotheses: disparities in trials of calcium supplementation during pregnancy. Am J Clin Nutr 2000;71(5 Suppl):1375S–9S [review].
75. Koo WWK, Walters JC, Esterlitz J, et al. Maternal calcium supplementation and fetal bone mineralization. Obstet Gynecol 1999;94:577–82.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.