Related post – Prenatal steroids to prevent boyish baby girls (5/19/11)
On 10/19/11 Science Translational Medicine published the research of Dr Emily Tam, MD, assistant clinical professor of child neurology at UCSF, et al demonstrating Preterm Cerebellar Growth Impairment After Postnatal Exposure to Glucocorticoids. Per study abstract:
“As survival rates of preterm newborns improve as a result of better medical management, these children increasingly show impaired cognition. These adverse cognitive outcomes are associated with decreases in the volume of the cerebellum. Because animals exhibit reduced preterm cerebellar growth after perinatal exposure to glucocorticoids, we sought to determine whether glucocorticoid exposure and other modifiable factors increased the risk for these adverse outcomes in human neonates.”
MRI studies were performed on 172 premature infants exposed to steroids before birth in order to evaluate resultant structural abnormalities of the brain. Betamethasone (the drug of choice to minimize the risk of neonatal respiratory distress syndrome in premature infants) was not associated with measurable differences from controls. However, both dexamethasone (DEX) and hydrocortisone were associated with an 8-10% decrease in the size of the cerebellum, the part of the brain responsible for motor control, balance and cognitive function. The association between cerebellar hypoplasia and impaired motor and cognitive function is well established.
So what does this have to do with congenital adrenal hyperplasia (CAH)? As discussed in my earlier post, Prenatal steroids to prevent boyish baby girls, DEX is a controversial treatment offered to women at risk of having a female fetus with CAH with the only aim being to avert masculinization of her genitalia (enlargement of the clitoris, fusion of the labia and elongation of the urethra). This treatment unnecessarily exposes 7 out of 8 fetuses to high levels of DEX (60 times higher than a normal physiologic level) and many of those female fetuses with CAH aren’t even at risk.
This article provides further evidence that DEX is dangerous, shrinks brains in addition to clitorises and may result in lifelong deficits in motor and cognitive capabilities. Other known risks for babies are:
- Decreased birth weight
- More shyness, social anxiety and emotionality
- Less sociability
- Poorer working memory (ie reading comprehension) and self-perceived scholastic competence
- Less masculine males with more neutral gendered behaviors
DEX treatment is NOT the standard of care, it is experimental and controversial and mounting evidence continues to demonstrate that its risks outweigh its benefits.
“Physicians should not sell themselves short in imagining that they cannot — with their words as much as with their knives and drugs — influence parents to accept their children’s bodies and the possibility that their children could lead rewarding lives with those bodies.”
– Dr Elizabeth Reis, PhD