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


METHODS
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.


CONCLUSIONS
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.
Makrides
Maria
M
Child Nutrition Research Centre, Child Health Research Institute, and Department of Paediatrics, University of Adelaide, Women's & Children's Hospital, North Adelaide, SA, Australia. makridesm@mail.wch.sa.gov.au
Crowther
Caroline A
CA
Gibson
Robert A
RA
Gibson
Rosalind S
RS
Skeaff
C Murray
CM
D000328:Adult; D018798:Anemia, Iron-Deficiency / Q000453:epidemiology / Q000517:prevention & control*; D003677:Deficiency Diseases / Q000453:epidemiology; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006304:Health Status; D006801:Humans; D015994:Incidence; D007501:Iron / Q000008:administration & dosage* / Q000009:adverse effects; D000090463:Iron Deficiencies; D019266:Iron, Dietary / Q000008:administration & dosage; D010349:Patient Compliance; D011247:Pregnancy / Q000097:blood / Q000502:physiology*; D011248:Pregnancy Complications / Q000453:epidemiology; D011256:Pregnancy Outcome; D039401:Prenatal Nutritional Physiological Phenomena; D016896:Treatment Outcome; D015032:Zinc / Q000097:blood
D019266:Iron, Dietary; D007501:Iron; D015032:Zinc