It cannot be said to be a symptom of pregnancy, but one of the conditions that accompany pregnancy. There is a difference between these two. Symptoms are the particular conditions that will tell that you are pregnant. Having diarrhea will not tell that you are pregnant, you can have diarrhea because of tens of other conditions. So, is diarrhea a symptom of pregnancy? No it is not, it is just one of the conditions that come with being pregnancy. Besides it will not happen in the first few weeks of pregnancy and by the time you have diarrhea, you have already known that you are pregnant. The reason you will diarrhea in pregnancy varies depending on its cause. Hygiene is not particular to pregnancy, so you can diarrhea in pregnancy and out of pregnancy because of hygiene. The particular reason for diarrhea in pregnancy is the change in diet and exercise routines that will affect the way you body operates. It is important that any changes during pregnancy to accommodate the baby should be done slowly,so that the body is used to the changes and so that you can prevent diarrhea. You should take a lot of water so that you are not dehydrated as well.