Researchers have found the placenta may contain a marker for autism. They found that placentas with unusual folds trap a certain type of cell called trophoblasts. These trappings can be seen via microscope and are called inclusions. Researchers have found children diagnosed with autism spectrum disorder have more than three times the amount of inclusions versus children who aren't. This research could be utilized as an early detection tool once more research in this area has been completed.
You can read the full article here: http://www.news-medical.net/news/2006/06/27/18586.aspx.
I think that even if this research were to become a tool for early detection, I still feel it is important to remember that autism, like all disorders of the body, are multi-faceted. They often have multiple causes and multiple treatments. This is why western medicine fails so miserably at curing many conditions because there simply isn't a pill or drug that can be taken to fix every problem. Autism more than likely has more than one cause, especially since each person is so individual, and the key will be addressing the cause for each person. Of course, this research shows how important the placenta is becoming as we find out more information about it. But I don't believe for a second that all cases of autism can be linked simply directly to the placenta. We also know autism is linked to allergies. It is more than likely linked to vaccines. So, while this research may prove worthwhile and having a healthy placenta is certainly important, it may turn out that not all cases of autism will be able to be detected from the placenta and early diagnosis is not at all the same as a cure.