38 Daily vs. Intermittent Iron Therapy in Moderate Iron Deficient Pregnant Patients: A Randomized Non-inferiority Trial

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Conference Proceeding

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American journal of obstetrics and gynecology


Objective: Evaluate the hematological response of pregnant women to iron therapy in daily vs. intermittent treatment groups & evaluate gastrointestinal side effects & adherence to therapy.

Study Design: A pragmatic non-blinded randomized controlled non-inferiority trial performed at two medical sites. Pregnant women undergoing routine prenatal labs at 26-29 weeks gestation were approached about the study. Exclusion criteria were: diagnosed iron deficiency anemia < 26 weeks, already on iron supplementation, had a condition known to affect iron metabolism. Enrolled patients were randomized to supplemental iron daily or intermittently (every other day). The primary outcome was change in hemoglobin (Hgb) after treatment, with the non-inferiority margin set at 1 Standard Deviation (SD) ( 0.5 g/dL Hgb). Secondary outcomes were: differences in other hematological indices (hematocrit, mean corpuscular volume, serums transferrin receptor molecule, hepcidin, ferritin, calculated body iron store), gastrointestinal side effects & adherence. We assumed a mean increase of Hgb was 1 g/dL in the daily group. A 0.5 g/dL or more mean Hgb difference between groups was considered clinically significant. With a two sided, two-sample t-test, to achieve a power of 90%, α of 0.05, 23 patients per group were needed.

Results: One hundred seventy-nine women were screened & 58 met study criteria, 29 were randomized to daily & 29 to intermittent iron groups. Twenty-two patients were analyzed in the daily group & 24 patients were analyzed in the intermittent group. Baseline characteristics were not different between groups (p >.05). Intermittent iron therapy was non-inferior to daily therapy, with a mean SD difference of 0.27 g/dL (95% CI: -0.33 to 0.89) (Figure). Changes in other hematological indices were not significant (Table). Women in the daily group had more nausea compared to intermittent group (p = 0.040). Women in the intermittent group were not more adherent with therapy (p=0.244).

Conclusion: Intermittent iron therapy is non-inferior to daily iron therapy and is associated with less nausea but not increased adherence.





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