Topic: Prenatal exposure to alcohol can alter the development of the nervous system and can alter behaviour and cognition in later life. These developmental abnormalities are commonly referred to as foetal alcohol spectrum disorders (FASD). A wealth of evidence from human clinical studies and animal models have identified some important molecular pathways, physiological processes and brain regions that may be disrupted by prenatal exposure to alcohol. In this essay discuss the symptoms of FASD and the physiological processes and brain structures that might be involved and hence why we think the impairment occurs.
1. Amount/ period of alcohol consumption
3. Affected structures
4. Physiological processes that cause impairment
Consumption of alcohol during pregnancy can cause a number of Foetal Alcohol Spectrum Disorders (FASD) that can result in developmental abnormalities in the nervous system of an unborn foetus. This can result in impaired cognition and behaviour later in life. The extent to which cognition and behavioural development is affected depends on several factors: Primarily the regularity in which alcohol is consumed but also the amount that is consumed each time. FASD symptoms in those affected by heavy drinking during foetal development ranges from mild to severe abnormalities in cognition and behaviour. The physical structure of the brain can often be affected by prenatal drinking. Overall brain and cranial size is often reduced along with underdeveloped neural structures such as the corpus callosum. When consuming alcohol while pregnant, alcohol can enter the placenta and thus the foetus as well. The proliferation and migration of neurons in the foetus can be affected by the presence of alcohol and may lead to the development of a Foetal Alcohol Spectrum Disorder.(p103,ref2)
Throughout the gestation period the consumption of alcohol can affect the development of the foetus’s nervous system. Research into prenatal alcohol consumption in humans has been largely inconclusive due to variables such as genetic factors, cultural demographic and testing methods, however. Certain studies have shown that even moderate prenatal drinking can often result in a child developing a Foetal Alcohol Spectrum Disorder. Many children who were exposed to moderate amounts of alcohol while in the womb were shown to have impaired working memory and concentration(1) Studies conducted on rats have yielded more information on the effects prenatal consumption of alcohol can have on the development of the foetal nervous system. Just as has been shown in Humans, moderate prenatal alcohol exposure resulted in impaired learning and memory abilities in the offspring. (2) From these experiments, it is evident that Moderate exposure to alcohol often results in developmental abnormalities in offspring such as mood disorders, memory and the ability to concentrate. Moderate prenatal drinking rarely results in a child developing full symptoms of FASD but rather subsets or less severe effects of the disorder, however. Heavy or “binge drinking” is shown to increase the likelihood of FASD occurring in its full effect. The more often prenatal “heavy drinking” occurs the more likely a child is to be born with FASD. Data from cultures where “binge drinking” is common (such as with Indigenous Australians ) shows a much higher prevalence of FASD than occurs in cultures where binge drinking is less common. (3)(5)
The symptoms of an FASD are varied in their effects and severity in each case. FASD’s while all being caused by prenatal alcohol exposure are not necessarily the condition FASD itself. Many different combinations of symptoms result in various forms of the condition. The condition Foetal Alcohol Spectrum Disorder is the most severe result of prenatal drinking. In mild to moderate cases an FASD may cause an affected child to have difficulty with concentration and working memory. More severe cases