Animal studies suggest spirulina has anti-toxic effects and nutritional benefits in pregnant rats and mice, but how safe is it for pregnant women? Although there’s little data on consuming spirulina during pregnancy, and toxins produced by other blue-green algae have reportedly been found in small amounts in some spirulina products, significant levels of heavy metals like mercury or lead haven’t been found in spirulina products. Toxins from blue-green algae, which may damage the liver and nervous system and are especially dangerous for infants, small children, and presumably foetuses, are probably reduced due to how most spirulina is now cultivated—in controlled settings and using technologies that minimise risk and monitor for contamination.

With all of this in mind, eating products such as food bars and powders fortified with spirulina is likely safe for pregnant women. However, women who want to use spirulina supplements or products during pregnancy should be conscientious about choosing products that are reliably inspected for purity. Also, they should consult a doctor before taking new supplements or making dietary changes.

Source: Food and Chemical Toxicology