Efficacy and tolerability of low-dose iron supplements during pregnancy: a randomized controlled trial

Am J Clin Nutr. 2003 Jul;78(1):145-53. doi: 10.1093/ajcn/78.1.145.

Abstract

Background: Iron deficiency anemia (IDA) is common in pregnant women, but previous trials aimed at preventing IDA used high-dose iron supplements that are known to cause gastrointestinal side effects.

Objective: The objective was to assess the effect on maternal IDA and iron deficiency (ID, without anemia) of supplementing pregnant women with a low dosage (20 mg/d) of iron. Effects on iron status were assessed at the time of delivery and at 6 mo postpartum. Gastrointestinal side effects were assessed at 24 and 36 wk of gestation.

Design: This was a randomized, double-blind, placebo-controlled trial of a 20-mg daily iron supplement (ferrous sulfate) given from 20 wk of gestation until delivery.

Results: A total of 430 women were enrolled, and 386 (89.7%) completed the follow-up to 6 mo postpartum. At delivery, fewer women from the iron-supplemented group than from the placebo group had IDA [6/198, or 3%, compared with 20/185, or 11%; relative risk (RR): 0.28; 95% CI: 0.12, 0.68; P < 0.005], and fewer women from the iron-supplemented group had ID (65/186, or 35%, compared with 102/176, or 58%; RR: 0.60; 95% CI: 0.48, 0.76; P < 0.001). There was no significant difference in gastrointestinal side effects between groups. At 6 mo postpartum, fewer women from the iron-supplemented group had ID (31/190, or 16%, compared with 51/177, or 29%; RR: 0.57; 95% CI: 0.38, 0.84; P < 0.005). The rate of IDA between the groups did not differ significantly at 6 mo postpartum.

Conclusion: Supplementing the diet of women with 20 mg Fe/d from week 20 of pregnancy until delivery is an effective strategy for preventing IDA and ID without side effects.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anemia, Iron-Deficiency / epidemiology
  • Anemia, Iron-Deficiency / prevention & control*
  • Deficiency Diseases / epidemiology
  • Dietary Supplements*
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Female
  • Health Status
  • Humans
  • Incidence
  • Iron / administration & dosage*
  • Iron / adverse effects
  • Iron / deficiency*
  • Iron, Dietary / administration & dosage
  • Patient Compliance
  • Pregnancy / blood
  • Pregnancy / physiology*
  • Pregnancy Complications / epidemiology
  • Pregnancy Outcome
  • Prenatal Nutritional Physiological Phenomena*
  • Treatment Outcome
  • Zinc / blood

Substances

  • Iron, Dietary
  • Iron
  • Zinc