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.