Vegetarian diets and global disparities in calcium intake in pregnant women: A systematic review and meta‐analysis

Background Vegetarian diets are currently experiencing increasing popularity and are also becoming more common in pregnant women. Calcium plays a crucial role for skeletal health and for physiologic processes during pregnancy for the mother and foetus. Aims Our study aimed to evaluate calcium intake of vegetarian versus nonvegetarian expectant mothers. Materials and Methods We searched PubMed and retrieved seven studies (six prospective cohort and one cross‐sectional) for inclusion in our random‐effects meta‐analysis. We calculated standardised mean differences (SMD). Results Results showed a significantly higher calcium intake in vegetarian than nonvegetarian pregnant women [SMD: 0.25; 95% confidence interval (CI): 0.14, 0.36]. Discussion Most studies showed that the recommendations for calcium intake during pregnancy (ranging from 700 to 1200 mg/d) were met. Both vegetarian and nonvegetarian pregnant women showed higher calcium intakes in Europe and North America than in Asia. Serum calcium levels did not differ between vegetarian and nonvegetarian pregnant women (SMD: − 0.15; 95% CI: −0.42, 0.11), confirming that the tight regulation of calcium metabolism is not affected by dietary calcium intake. Conclusion To prevent inadequate calcium intake potentially associated with adverse gestational outcomes, we recommend adherence to existing recommendations by means of calcium supplementation (1.5–2 g/d), food fortification strategies, or behavioural interventions.