16111
Low Maternal Progesterone and Autism
Increasingly, researchers have hypothesized that maternal environment could be as important, if not more important, than genetics as a factor contributing to autism. For over 30 years, studies have shown an increased autism risk among children born to mothers experiencing obstetrical complications. Although this is usually interpreted as suggesting that the obstetrical complications could be causing autism, it is equally likely that a single factor could be responsible for both complications and autism. We are proposing that this factor is low maternal progesterone.
Progesterone is not only necessary for a healthy pregnancy; it is also a brain developmental factor, important for myelination, dendritic development, neurogenesis and development of the serotonergic neurotransmitter system. Importantly to our hypothesis, progesterone available to the developing fetal brain is only that which is supplied by the mother.
Objectives :
We proposed to test our hypothesis that low levels of the hormone progesterone are responsible for some cases of autism, by determining the number of progesterone-related obstetrical events in mothers of autistic children.
Methods:
In order to test this hypothesis, we conducted a survey of mothers of autistic children (n=86) compared to mothers of typically-developing children (n=88) regarding obstetrical histories, including five obstetrical events indicative of low progesterone: contraceptive failure, excess weight gain, vaginal bleeding, fertility treatments and low fertility.
Results:
Using this analysis, the ASD group had significantly more risk factors indicating low progesterone than controls (1.21 ± 0.09 vs. 0.76 ± 0.08, p< .0001),
Conclusions:
Our results support our hypothesis that low progesterone may be responsible for both obstetrical complications and brain changes associated with autism. Moreover, low progesterone could explain the male preponderance of autism (since only the developing male brain expresses progesterone receptors) and the increased incidence of autism could be explained by advances in fertility and obstetrical management masking progesterone deficiencies. We are currently expanding our studies to determine the role of low progesterone in specific components of the autism spectrum.
Our work suggests that progesterone levels should be routinely monitored in at-risk pregnancies.