A randomized cross over trial of tolerability and compliance of a micronutrient supplement with low iron separated from calcium vs high iron combined with calcium in pregnant women [ISRCTN56071145]

BACKGROUND: Prenatal micronutrient combinations with high iron content are associated with high rates of gastrointestinal symptoms. This coupled with nausea and vomiting of pregnancy results in women often discontinuing their multivitamins. A new prescription supplement (PregVit(®)) that separates iron from calcium in two tablets – morning and evening, has lower elemental iron content (35 mg), but results in similar extent of iron absorption when compared to another supplement containing (60 mg) of elemental iron (Materna(®)). The objectives of this study were to compare tolerability and compliance with PregVit(® )vs. a supplement with high iron content (Materna(®)), in pregnant women. METHODS: Randomized, crossover open labeled study in 135 pregnant women attending outpatient clinics in Ontario and Quebec. RESULTS: Use of PregVit(® )was associated with a 30% reduction in constipation rate as compared to Materna(®). Both products demonstrated similar compliance rates. Compliance of Materna(® )was negatively associated with the severity of nausea and vomiting of pregnancy. No such correlation was found for PregVvit(®). CONCLUSION: PregVit(®), a supplement with lower iron content (35 mg), has significantly decreased constipation rates as compared to 60 mg iron- Materna and has similar compliance rates. High iron content in multivitamin supplements is associated with adverse effects in pregnancy.