Gastrointestinal Complications of Ferrous Sulfate in Pregnant Women: A Randomized Double-Blind Placebo-Controlled Trial

BACKGROUND: Some pregnant women discontinue iron supplements consumption due to Gastrointestinal (GI) complications, whereas pregnancy induces the same complications physiologically. OBJECTIVES: The aim of the present study was to assess GI complications of ferrous sulfate in pregnant women. PATIENTS AND METHODS: This randomized, double-blind, placebo-controlled clinical trial was performed on 176 pregnant women referred to prenatal care clinic of Maryam Hospital from April 2011 to February 2012. Pregnant women with Hb ≥ 13.2 gr/dL at 13(th) - 18(th) weeks of gestation were selected based on the inclusion criteria and were randomly assigned to the ferrous sulfate and placebo groups. The ferrous sulfate group (n = 90) received a 50-mg ferrous sulfate tablet daily from the 20(th) week to the end of pregnancy and the placebo group (n = 89) received one placebo tablet in the same way. All participants were visited twice at 24(th) - 28(th) and 32(nd) - 36(th) weeks to assess the GI complications as well as Hb level to determine the Hb changes in two groups. Chi-square test, t-test and Kolmogorov-Smirnov test were used to analyze the data. P value of < 0.05 and confidence level of 95% were considered as statistically significant. RESULTS: None of the GI complications were significantly different between the ferrous sulfate and placebo groups at 24(th) - 28(th) and 32(nd) - 36(th) weeks. Hemoglobin drop lower than 10.5 gr/dL at 24(th) - 28(th) weeks or lower than 11 g/dL at 32(nd) - 36(th) weeks was not observed in any cases. CONCLUSIONS: It can be concluded that GI complications in pregnant women using ferrous sulfate are mostly caused by physiologic changes of pregnancy rather than ferrous sulfate; therefore, it is not reasonable to stop using ferrous sulfate due to GI complications.