High Levels of Oestrogens In the Womb Linked To Autism, Study Finds

An anonymous reader quotes a report from ScienceDaily: Scientist have identified a link between exposure to high levels of oestrogen sex hormones in the womb and the likelihood of developing autism. The findings are published today in the journal Molecular Psychiatry. In 2015, a team of scientists at the University of Cambridge and the State Serum Institute in Denmark measured the levels of four prenatal steroid hormones, including two known as androgens, in the amniotic fluid in the womb and discovered that they were higher in male fetuses who later developed autism. These androgens are produced in higher quantities in male than in female fetuses on average, so might also explain why autism occurs more often in boys. They are also known to masculinize parts of the brain, and to have effects on the number of connections between brain cells. Today, the same scientists have built on their previous findings by testing the amniotic fluid samples from the same 98 individuals sampled from the Danish Biobank, which has collected amniotic samples from over 100,000 pregnancies, but this time looking at another set of prenatal sex steroid hormones called oestrogens. This is an important next step because some of the hormones previously studied are directly converted into oestrogens. All four oestrogens were significantly elevated, on average, in the 98 fetuses who later developed autism, compared to the 177 fetuses who did not. High levels of prenatal oestrogens were even more predictive of likelihood of autism than were high levels of prenatal androgens (such as testosterone). “This new finding supports the idea that increased prenatal sex steroid hormones are one of the potential causes for the condition,” said Professor Simon Baron-Cohen, Director of the Autism Research Center at the University of Cambridge and author of the study. “Genetics is well established as another, and these hormones likely interact with genetic factors to affect the developing fetal brain.” The team cautioned that these findings cannot and should not be used to screen for autism.