Question: If a mother gets a cold at a certain time during her pregnancy, can that cause autism?
Answer: There are a number of studies suggesting that infections during pregnancy increase the risk of neuropsychiatric disorders. This includes autism but it also includes other things such as schizophrenia. The problem is not so much the infection as the way the body's immune system reacts to the infection. Learning about how our body's immune systems react during pregnancy and how they change the environment in which the fetus is developing is a very active area of research at this time.
So there is a possibility that this would increase the risk of autism. It's not clear whether it would cause autism so much as change the way the immune system responds in the future for the child and make the risk of other things affecting the child be greater.