PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Fetal alcohol syndrome (FAS) is the more severe end of a continuum of birth defects known as fetal alcohol spectrum disorders (FASDs).
Fetal alcohol effects (FAEs), otherwise known as alcohol-related birth defects (ARBDs), may represent the milder end of the spectrum.
Other terms for conditions which come under the umbrella of FASD are alcohol-related neuro-developmental disorder (ARND) and partial fetal alcohol syndrome (pFAS). These are caused by maternal use of alcohol during pregnancy.
There are three main components of FAS:
- Typical facial abnormalities
- Intrauterine growth restriction and failure to catch up
- Neuro-developmental abnormalities causing learning disability, cognitive impairment and behavioural problems
Alcohol is the most common teratogen affecting humans. It is rated as the most common non-genetic cause of mental and behavioural problems in children. Exact numbers are difficult to define in this spectrum of disorder and there are no accurate figures for prevalence in the UK. This is due to a number of factors, including the differing definitions and conditions along the spectrum, the poor accuracy in self-reporting of alcohol consumption, lack of standardisation of levels of drinking, reluctance to make or accept the diagnosis, and paucity of reliable data collection. Most figures come from the USA, where it is estimated that FAS occurs in 0.5-2 live births per 1,000 and fetal alcohol spectrum conditions occur at least three times as often as this.
There is much difference between communities, depending on habits and tradition. Studies across the world have shown vastly different figures for incidence of FASD as high as 40 per 1,000 children in Italy, and 89 per 1,000 in the Western Cape province in South Africa.
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The sole risk factor is maternal consumption of alcohol during pregnancy. Alcohol is a teratogenic substance which crosses the placenta with ease. Development of the fetus can be affected by alcohol at any stage. Different effects may occur depending on the stage of exposure, however.
Not all women who drink heavily during pregnancy have babies with FAS, and it is clear that other factors affect the vulnerability of the fetus. These include the stage of pregnancy affected, the pattern of drinking, the health, age, stress levels and nutritional status of the mother and the use of other toxic substances, including tobacco. Genetic makeup and gene polymorphisms also affect fetal vulnerability for FAS, and other genetic abnormalities can be confused with FAS.
There has been enormous debate about the safe level of alcohol in pregnancy; there have also been many studies to try to ascertain the effects of different levels and patterns of drinking. National Institute for Health and Care Excellence (NICE) guidelines on antenatal care detail some of these, and attempt recommendations on the basis of them. Studies are not conclusive and many feel total abstinence is the safest advice. In the UK, NICE guidelines, the British Medical Association (BMA) guidance and the Royal College of Obstetricians and Gynaecologists (RCOG) statement concur that women should be advised to abstain if possible in view of the uncertainty, and in particular in the first three months, due to the increased risk of miscarriage. If women choose to drink alcohol, they are advised to have no more than 1-2 units of alcohol no more than 1-2 times a week, as there is no evidence of harm at this level. They are also advised that binge drinking may harm the baby.
The fact of alcohol abuse may not be known to others. Alcoholism, diagnosis and treatment in primary care can be very difficult and self-reported levels of consumption must be treated with circumspection.
Diagnosis of FAS and FASD is difficult. There is no test, so diagnosis depends on a history or suspicion of in-utero alcohol exposure, and the presence of typical clinical features. Criteria for diagnosis vary, and are better defined for FAS than other conditions within the spectrum, so it is not surprising that prevalence figures are a challenge to establish.
Failure of growth
Weight, length and head circumference are all reduced and, whilst the infant who has suffered from placental insufficiency tends to emerge ravenous and eagerly feeds to restore weight, the child with FAS remains stunted for life. Adequate nutrition and a caring environment are not enough to reverse the damage.
These may include any permutation of the following:
- Microcephaly (small head)
- Flat philtrum (flattening of the groove under the nose)
- Thin upper lip
- Retrognathia in infancy, micrognathia or relative prognathism in adolescence and a low nasal bridge
- Microphthalmia, strabismus, ptosis and short palpebral fissures
- Cleft palate - may occur
- Posterior rotation of the ears
These may include:
- Low IQ, but can be normal or even higher than average
- Attention deficits
- Memory problems
- Problems with perceiving consequences, and inability to learn from experience. Poor judgement
- Poor problem-solving skills
- Immature behaviour. Poor social skills and lack of control of impulsive behaviour
- Poor co-ordination
- Speech and language delay
- Difficulty with concepts such as maths, money and time
- Sucking and feeding problems in the neonate. Occasionally, features of delirium tremens due to alcohol withdrawal
These first three categories of abnormality are the classic triad of FAS, but alcohol may have had further effects on the developing fetus, including:
These range from contractures of the finger joints to more severe lesions, such as developmental dysplasia of the hip and abnormalities of the thoracic cage.
These include cryptorchidism and hypoplastic labia as well as other abnormalities of the kidneys and urinary tract.
Hearing and visual impairments
There may be partial deafness and significant visual disability.
Some of these features can be measured and ranked by criteria such as the 4-Digit diagnostic code; however, there are several different systems with differing criteria. Moreover, some of these guidelines cover FAS, whereas others address the full FASD continuum.
Other conditions within the fetal alcohol spectrum disorder definition
The scale of the problem of the FASD as a whole is difficult to determine, as it may not be recognised as such without the classic criteria for FAS (ie growth restriction, typical facial anomalies, neuro-developmental abnormalities). The milder cases may be less likely to be diagnosed. The conditions under this umbrella describe any of the disabilities which may be caused by maternal drinking in pregnancy, and which may occur in isolation or as more than one.
Conditions on the lower end of the spectrum compared to FAS include pFAS, FAE or ARBDs, and ARND. Clinical features of these conditions are less well defined.
As children with FAS mature into adolescence and adulthood the craniofacial deformities become less noticeable but the short stature and microcephaly remain.
There may be more likelihood of other stresses and major life events in a childhood of a baby born to a mother who drinks heavily, which may further affect them. Educational achievement may be extremely limited. Children with FAS are more likely to have been in trouble in school and have poor relationships and, as they grow up, be more likely to be in trouble with the law, have inappropriate sexual relationships, mental health issues, addictive behaviours, and difficulty living independently. Impulsivity, poor judgement and lack of comprehension cause adults born with FAS to experience major psychosocial and adjustment problems for the rest of their lives.
Factors improving outcome include early recognition and diagnosis, support, a stable home life, a lower IQ, which may make the disability more apparent and make the patient less vulnerable to expectation of normality.
Both FAS and FAEs are entirely preventable. The pattern of alcohol consumption in this country has shown a marked rise since 1990 in total intake and in binge drinking, especially amongst young women, although the trend showed some reduction from 2006 in the latest report from the Office for National Statistics. These figures also show that the vast majority of women do not drink more than the guidelines recommend during pregnancy. Health promotion must continue to emphasise the need for moderation, if not complete abstinence, perhaps from before conception. Doctors, midwives and even nurses giving advice about family planning must emphasise the dangers of alcohol in pregnancy. The social and economic costs are enormous. The dangers of alcohol in pregnancy must be as well known as the dangers of smoking.
Alcohol has been used and abused since antiquity, but FAS was unrecognised until it was first described in France in 1968 and again in the USA in 1973. That is not to suggest that problems were previously unnoticed. During the 'gin epidemic a report from the Royal College of Physicians in 1725 noted that 'weak, feeble and distempered children' were the result. In 1834 a parliamentary report 'Effects of Drunkenness on the Nation' remarked that children tend to be 'born starved, shrivelled and imperfect in form'.
Further reading & references
- Fetal alcohol spectrum disorders. A guide for healthcare professionals; BMA Board of Science, 2007
- Fetal Alcohol Spectrum Disorders; Centers for Disease Control and Prevention
- Blackburn C et al; Facing the challenge and shaping the future for primary and secondary aged students with Foetal Alcohol Spectrum Disorders (FAS-eDProject) Literature Review, National Organisation on Fetal Alcohol Syndrome UK, September 2009
- Warren KR, Li TK; Genetic polymorphisms: impact on the risk of fetal alcohol spectrum disorders. Birth Defects Res A Clin Mol Teratol. 2005 Apr;73(4):195-203.
- Antenatal care for uncomplicated pregnancies; NICE Clinical Guideline (March 2008)
- Mukherjee RA, Hollins S, Abou-Saleh MT, et al; Low level alcohol consumption and the fetus. BMJ. 2005 Feb 19;330(7488):375-6.
- Alcohol Consumption and the Outcomes of Pregnancy; Royal College of Gynaecologists, March 2006
- Burd L, Deal E, Rios R, et al; Congenital heart defects and fetal alcohol spectrum disorders. Congenit Heart Dis. 2007 Jul-Aug;2(4):250-5. doi: 10.1111/j.1747-0803.2007.00105.x.
- Astley SJ; Comparison of the 4-digit diagnostic code and the Hoyme diagnostic guidelines for fetal alcohol spectrum disorders. Pediatrics. 2006 Oct;118(4):1532-45.
- A report on the 2011 general lifestyle survey - Chapter 2: Drinking, Office for National Statistics (March 2013)
- Walker DS, Fisher CS, Sherman A, et al; Fetal alcohol spectrum disorders prevention: an exploratory study of women's use of, attitudes toward, and knowledge about alcohol. J Am Acad Nurse Pract. 2005 May;17(5):187-93.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Hayley Willacy
Dr Mary Harding
Dr Hayley Willacy