Drinking or smoking whist pregnant can harm your baby. This will be nothing new to most people, and it may seem obvious that you should look after yourself while pregnant. But now, writing in the journal PNAS, researchers Suzhen Chen and Michael Charness at Harvard Medical School have identified one mechanism through which alcohol damages the developing central nervous system.
It may surprise you to hear that despite us having known for years that drinking during pregnancy is bad for the developing foetus, exactly why and how is still quite unclear. What we do know is that the likelihood of ‘Fetal alcohol spectrum disorders’ is enhanced when expectant mothers drink alcohol. Fetal alcohol spectrum disorders, as the name suggests, encompass a number of developmental disorders of the brain, in particular in a region of the brain called the cerebellum.
Looking at the cerebellum, you would see large amounts of a chemical called Activity-dependent neuroprotective protein, or ADNP. ADNP is a protein derived from astrocytes – cells which support the neurons in the brain, and has an essential role in promoting healthy growth of nerve cells, as well as protecting them from damage. One key part of ADNP, called NAP, works to encourage nerve growth by activating a factor called ‘Fyn Kinase’ and a scaffold protein called crk-associated substrate, or CAS. When working properly, these two factors encourage the growth of axons – the long connecting parts of nerve cells. When Chen and Charness chemically inhibited Fyn Kinase, nerve growth stopped.
So how does alcohol come into this? It seems that even a relatively small amount of alcohol, concentrations similar to that found in a woman’s bloodstream after consuming just two drinks within an hour, stops NAP from activating Fyn Kinase. This means that nerves cannot develop, leading to the developmental problems that can be seen in fetal alcohol spectrum disorders.
Clearly, the advice is still that you should not drink whilst pregnant, but at least we’re getting closer to understanding how alcohol has such an effect on a developing brain.