Black stool of pregnant women may be related to food, drugs and other factors, if the symptoms are serious, it may be related to gastric, duodenal ulcer and other diseases caused by upper gastrointestinal bleeding. 1. Food, drugs and other factors: If you eat food or drugs containing iron, such as pig’s blood, pig’s liver, ferrous sulfate, etc., may lead to black stools, mainly due to the reaction between iron and hydrogen sulfide in the intestinal tract, usually do not need special treatment, and can be restored after stopping consumption. 2. Upper gastrointestinal bleeding: if accompanied by vomiting blood, dizziness, fatigue and other symptoms, it is considered that it may be related to upper gastrointestinal bleeding caused by esophageal, gastric and duodenal ulcers, etc. It is mainly due to the combination of hemoglobin and sulfide, the formation of ferrous sulfide, which will make the stool appear black. If the stool is black, it is recommended that pregnant women seek medical attention. If it is caused by upper gastrointestinal bleeding, it can be treated by rehydration and endoscopic hemostasis as prescribed by the doctor.