Black stool when pregnant

Prenatal vitamins and prescribed iron commonly make bowel movements dark. Dark foods or bismuth-containing products may do the same. Stool that is tar-like, sticky, unusually smelly, or accompanied by weakness is more concerning for melena, meaning digested blood from the upper digestive tract. Gastritis, peptic ulcer, and Helicobacter pylori infection can be possible causes and need professional assessment.

Check the label of supplements and note the timing of the colour change, but do not stop prescribed iron without speaking with your maternity or primary-care team. Tell them about abdominal pain, nausea, vomiting, bowel frequency, and every medicine or supplement you use. Drink normally if you can keep fluids down. Do not self-treat with pain relievers or stomach remedies without pregnancy-specific advice.

Seek emergency care for black stool with fainting, dizziness, severe weakness, shortness of breath, severe abdominal pain, vomiting blood, or coffee-ground vomit. Contact your maternity team promptly if black stools recur, look tarry, or have no clear link to iron or food. If you feel faint, ask someone else to take you for care.

Ask whether your iron preparation explains the colour, whether the stool needs testing, and which pregnancy-safe treatments are appropriate. Ask how to distinguish expected supplement effects from symptoms of gastritis, a peptic ulcer, or Helicobacter pylori infection.