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Clinical research: Placenta’s structure signals autism risk

Abnormal cells in the placenta, usually discarded at birth, may be early indicators of autism, suggests a study published 22 April in Biological Psychiatry.

By Jessica Wright

7 June 2013 | 1 min read

This article is more than five years old.

Neuroscience—and science in general—is constantly evolving, so older articles may contain information or theories that have been reevaluated since their original publication date.

Abnormal cells in the placenta, usually discarded at birth, may be early indicators of autism, suggests a study published 22 April in Biological Psychiatry¹. The study found that trophoblastic inclusions, abnormal folds in the placenta, are more common in babies at risk of developing autism than in controls.

This characteristic abnormality could serve as an early biomarker of autism, which is normally diagnosed only once children reach 3 years of age. Early behavioral interventions may give children the best chance of improving their symptoms.

The researchers initially discovered that preserved placentas from 5 of 13 babies who went on to develop autism have these abnormal cells, compared with 8 of 61 controls².

In the new study, they looked at 217 placentas: 117 from siblings of children with autism and 100 from controls. About 20 percent of siblings of children with autism develop the disorder.

Among the high-risk babies, 77 of the placentas have at least one inclusion, and 48 have more than one. By contrast, 32 of the 100 controls have at least one inclusion, and 8 have more than one. Only high-risk placentas, 28 in total, have three or more inclusions, and 4 of them have more than 10.

The researchers intend to follow up with both sets of babies in a few years so that they can confirm a link between the abnormal cells and an eventual autism diagnosis.

The trophoblast inclusions are a sign that cells multiplied too quickly during early development. Similar abnormalities may develop in other structures in the fetus.

The results are not necessarily specific to autism, however. Studies have shown that babies with chromosomal abnormalities visible under a microscope are more likely than controls to have trophoblast inclusions³.