It is important to note that changes in bowel movements can occur during pregnancy, and variations in stool color are generally not a cause for alarm. However, if you notice that your stool has turned black, it could indicate an underlying issue that requires medical attention. Black stools can be caused by certain medications, iron supplements, or even certain foods. However, they can also be a sign of bleeding in the upper gastrointestinal tract. If you experience other symptoms such as abdominal pain, dizziness, or weakness along with black stools, it is crucial to consult your healthcare provider immediately. They will be able to evaluate your specific situation and provide appropriate guidance and treatment if necessary.