Scientists have recently identified what they believe to be a definitive link between exposure of high levels of the estrogen sex hormone in the womb and autism risk.
It all started in 2015, when a team of scientists at the University of Cambridge came together with State Serum Institute researchers, in Denmark. Collectively, they measured and analyzed the levels of four prenatal steroid hormones in the amniotic fluid (in the womb). Including two known androgen steroid hormones, they found that these hormones were higher among male fetuses who went on to develop autism down the road.
Furthermore, they determined these androgens are produced in higher quantities among male fetuses than female fetuses, on average. Effectively, the team argues, this might explain why autism tends to occur more often in boys than in girls. These hormones have also been known to “masculinize” parts of the brain, ultimately effecting the number of neural connections.
Using the previous study as a platform for new discovery, the same group of scientists tested the amniotic fluid samples taken from 98 individuals as part of the Danish Biobank (which has collected more than 100,000 amniotic samples from pregnancies). This time, however, the team specifically looked at the prenatal sex steroid hormone called estrogen.
In the newest study, the researchers found that all four types of estrogen were significantly higher, on average, among those 98 fetuses who had later developed autism compared to the 177 fetuses who did not develop autism. The researchers also noted higher levels of prenatal androgens (including testosterone). Apparently this contradicts that popular belief that links estrogen with feminine development, the study observed how prenatal estrogen can have various effects on brain development, including masculine brain development among mammals.
While the team celebrates the results, they also caution that the findings are still preliminary. As such, they warn that this data should not be used as a strategy for autism screening. It is certainly a worthy discovery, but the data is best used for better understanding some of the mechanisms of autism and not necessarily as a means for diagnosis or prevention.