prenatal estrogen levels

New evidence reveals that exposure to higher prenatal estrogen levels may be predictive of a higher risk of autism.

Males are three times more likely to be diagnosed with autism than females. This male bias for autism has suggested that sexual differentiation may be involved with its development. Although autism is strongly heritable and specific genetic-related mechanisms contribute to its development, the amount of exposure to prenatal hormones that play an important role in sexual differentiation might also be a factor in autism.

Prenatal estrogen plays a role in neurodevelopmental processes in the brain that are often found to be abnormal in autism. Despite this association, estrogen’s specific role in the development of autism has not been well studied.

In a recent study published in Molecular Psychiatry, scientists in Denmark and the UK evaluated the association between prenatal estrogen levels and the risk of autism. The scientists had previously conducted a study that discovered a higher level of steroid hormone activity in the amniotic fluid of male fetuses that went on to develop autism. In this new study, they used the same amniotic fluid samples from their previous study to investigate whether there was a link between autism and prenatal estrogen levels.

The scientists found that prenatal estrogen levels were the highest predictor of autism and were significantly associated with an autism diagnosis. Prenatal estrogen levels were a greater contributor to the likelihood of autism compared to other steroid sex hormones, including testosterone.  It is thought that exposure to higher prenatal estrogen levels may cause disruptions in the prenatal brain development that leads to autism. At present, their findings can only be applied to autism in males because they only tested amniotic fluid samples from males.

This study builds on previous evidence implicating the role of steroid hormone activity levels on the development of autism and supports the prenatal steroid theory of autism. The scientists conclude that an excess level of prenatal estrogens is characteristic of autism and plays a role in atypical brain development that can lead to autism. Future research should focus on studying all the possible sources of prenatal hormones and how they interact with each other during pregnancy. Importantly, the scientists want their findings to be used to better understand autism rather than for screening and preventing autism.

Written by Maggie Leung, PharmD.


Baron-Cohen, S., Tsompanidis, A., Auyeung, B., Nørgaard-Pedersen, B., Hougaard, D. M., Abdallah, M., . . . Pohl, A. (2019). Foetal oestrogens and autism. Molecular Psychiatry. doi:10.1038/s41380-019-0454-9

High levels of estrogen in the womb linked to autism. (2019, July 29). Retrieved from

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