Hello, Welcom to Healthcaremagic.com. I had gone through your question I can understand your concern. Iron supplements are safe during pregnancy so you don t need to worry. The black stools or Terry black stools are also harmless while taking iron supplement because when iron reacts with acid of stomach this causes blackness of stools. But iron supplements can also lead to gastric upset and sometimes may lead to erosion of gastric mucosa which can be associated with severe pain while taking food or after meals. Dizziness is also the side effect of iron supplements. So it looks to me that your symptoms are because of the said medicine. It is normal. Hope my answer will help you. Regards. Dr Muzaffar.