If you are 3 months pregnant and your stool is black, clinically it is often related to the following factors: firstly, it is caused by diet, for example, if you have taken iron containing medicines, it will make your stool appear black; if you have finished taking ferrous sulphate and then relieve your stool, it may be black, so you don’t need to be nervous about this. In addition, if you eat pig’s blood, the stool may also be black, so the color of the stool with the diet is directly related to the second, whether due to gastrointestinal bleeding caused by the black color of the stool, it is recommended that the best is to check the stool routine, to find out whether there is the possibility of occult blood, if there is occult blood, it is likely that the gastrointestinal tract bleeding caused by the suggestion to go to gastroenterology to do a further examination, according to the results of the examination of the clinic to give The best thing to do is to check the stool routine to find out the possibility of occult blood.