Effect of Daily Antenatal Iron Supplementation on Plasmodium Infection in Kenyan Women

Susan Kellum, Mercer University College of Pharmacy

According to the World Health Organization (WHO), anemia in pregnancy is a severe health problem worldwide, but especially in Africa. Iron deficiency in pregnancy has been associated with severe anemia and maternal death.1 A meta-analysis of randomized trails of iron supplementation during pregnancy found no evidence of benefits for maternal and neonatal health outcomes.2 However, international guidelines suggest pregnant women should receive daily iron supplementation. 3 This study aimed to assess effects of iron supplementation on gestational age at delivery, newborn size, and maternal and neonatal iron status at 1 month postpartum. 4

Title: Effect of daily antenatal iron supplementation on Plasmodium infection in Kenyan women4
Design Randomized, double-blind, placebo-controlled (N = 470)
Objective To measure the effect of antenatal iron supplementation on maternal Plasmodium infection risk, maternal iron status, and neonatal outcomes.
Study Groups Two parallel groups of pregnant women receiving daily iron supplementation (n = 237), and those without iron in the placebo group (n = 233).
Methods Researchers administered supplements daily and watched that women swallowed their supplement. The iron supplement contained 60 mg of elemental iron as ferrous fumarate. Women were referred to regular health services for routine antenatal and medical care during intervention. Birth weight was measured immediately after delivery, or on presentation in the research clinic. Supplementation with iron or matching placebo continued for one month postpartum.
Duration October 2011- April 2013
Primary Outcome Measure Defined as past or present maternal Plasmodium infection assessed at parturition
Baseline Characteristics Rural Kenyan women aged 15-45 years with singleton pregnancies, gestational age of 13 to 23 weeks, and hemoglobin concentration of 9 g/dL or greater were included in the study.

Baseline characteristics were similar with regard to height and weight, age, gestational age, gravidity, Plasmodium infection, HIV infection, plasma CRP concentration, inflammation (measured by CRP concentration), hemoglobin, blood count, and intestinal helminth infections. *Refer to study for all baseline characteristics.

Results Intention-to-treat analysis yielded the following results at birth:
  Iron Group Placebo Group P-value
Plasmodium infection risk 50.9% 52.1% 0.83
Birth weight 3202 g 3053 g 0.002
Birth weight for gestational age z score 0.52 0.31 0.20
Maternal hemoglobin concentration 12.89 g/dL 11.99 g/dL <0.001
Mean maternal plasma ferritin concentration 32.1 μg/L 14.4 μg/L <0.001
Mean neonatal plasma ferritin concentration 160.0 μg/L 138.7 μg/L 0.02
Adverse Events Common Adverse Events: None
Serious Adverse Events: Reported for 9 and 12 women who received iron and placebo, respectively.
Percentage that Discontinued due to Adverse Events: N/A
Study Author Conclusions Among rural Kenyan women with singleton pregnancies, administration of daily iron supplementation, compared with administration of placebo, resulted in no significant differences in overall maternal Plasmodium infection risk. Iron supplementation led to increased birth weight.

Anemia was defied as hemoglobin concentration less than 11g/dL. Among the 470 participating women, 40 women (22 iron, 18 placebo) were lost to follow-up or excluded at birth; 12 mothers were lost to follow-up postpartum (5 iron, 7 placebo). No evidence was found that indicated iron supplementation caused serious adverse events.4

The study concludes iron supplementation led to a decrease in the risk of low birth weigh by 64% (95% CI, 12-86). Correction of maternal iron deficiency led to an increase in birth weight by 239 grams. There is some evidence that intermittent preventive treatment (IPT) use modified the effect of iron on maternal hemoglobin concentration (P= 0.04 for interaction), but there was no monotonic trend in effect by IPT dose.4


  1. De Benois B, McLean E, Egli I, Cogswell M, eds. Worldwide Prevalence of Anaemia 1993-2005: WHO Global Database on Anaemia. Geneva, Switzerland: World Heath Organization; 2008.
  2. Peña-rosas JP, Viteri FE. Effects and safety of preventive oral iron or iron+folic acid supplementation for women during pregnancy. Cochrane Database Syst Rev. 2009;(4):CD004736.
  3. Kenya National Technical Guidelines for Micronutrient Deficiency Control. Nairobi, Kenya: Ministry of Public Health and Sanitation; 2008.
  4. Mwangi MN, Roth JM, Smit MR, et al. Effect of Daily Antenatal Iron Supplementation on Plasmodium Infection in Kenyan Women: A Randomized Clinical Trial. JAMA. 2015;314(10):1009-20.

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