Does Supplementation with Calcium During Pregnancy Affect the Mineral Concentration in Mature Breast-Milk?

Although the relationship between calcium intake during lactation and breast milk calcium concentration has been studied by many investigators, evidence available on the effects of calcium supplementation during pregnancy on the calcium content of breast-milk is limited. The aim of this double-blind placebo-controlled trial was to determine the effect of calcium supplementation during the 3rd trimester of pregnancy on the calcium concentration of mature breast-milk. Materials and Methods: Sixty-eight pregnant women in Ahwaz city, southwest Iran were randomly assigned to the "Calcium" (1 gr/d) or "Placebo" groups from the 28th-30th week of gestation until delivery. Breast-milk samples were taken 1.5 to 3 months after delivery. Calcium concentrations were measured using atomic absorption spectrometry. There were no significant differences between the two groups with respect to the demographic characteristics, anthropometric indices, and dietary energy and calcium intakes, at baseline. Results: No differences were found in calcium concentrations in mature breast-milk between the two groups [mean +/- SD were 228 +/- 38 and 235 +/- 42 mg/L in the calcium and placebo groups, respectively, (P=0.49)]. Conclusion: Our study did not support the hypothesis that calcium supplementation during pregnancy affects the calcium concentration later in mature breast-milk.