fetal alcohol spectrum disorder fetal alcohol spectrum disorder fetal alcohol spectrum disorders (fasds) are a group of conditions that can occur in a person who is exposed to alcohol as a result of their mother drinking during pregnancy. symptoms can include an abnormal appearance, short height, low body weight, small head size, poor coordination, behavioral problems, learning difficulties, and problems with hearing and sight. those affected are more likely to have trouble with school, the legal system, alcohol, other drugs, and other areas of high risk. the several forms of the condition (in order of most severe to least severe) are: fetal alcohol syndrome (fas), partial fetal alcohol syndrome (pfas), alcohol-related birth defects (arbd), static encephalopathy, alcohol-related neurodevelopmental disorder (arnd) and neurobehavioral disorder associated with prenatal alcohol exposure (nd-pae). as of 2016, the swedish agency for health technology assessment and assessment of social services accepted only fas as a diagnosis, seeing the evidence as inconclusive with respect to other types. fetal alcohol spectrum disordersother namesfoetal alcohol spectrum disorders, fasdbaby with fetal alcohol syndrome, showing some of the characteristic facial featuresspecialtypsychiatry, pediatrics, toxicology, embryology, neurologysymptomsabnormal appearance, short height, low body weight, small head size, poor coordination, behavior problems similar to those found in adhd, learning problemscomplicationsbabies: miscarriage, stillbirthadults: alcoholism, substance abuseusual onsetprenataldurationpermanenttypesfetal alcohol syndrome, partial fetal alcohol syndrome, alcohol-related neurodevelopmental disorder, static encephalopathy, alcohol-related birth defectscausesdrinking alcohol during pregnancydiagnostic methodbased on symptomsdifferential diagnosisadhd, autism, bipolar disorder, conduct disorder, learning disability, oppositional defiant disorderpreventionavoiding drinking alcohol during pregnancytreatmentparent-child interaction therapy, efforts to modify child behavior, possibly medicationsprognosisvaries depending on the individual, the level of alcohol exposure, and quality of living and educational arrangements. life expectancy can range from 31 to 37. average death age is 34.frequencybetween 1 in 20 (~390 million) and 1 in 13 (~600 million) fetal alcohol spectrum disorders are caused by the mother's drinking alcohol while pregnant with the affected person. surveys from the united states found that about 10% of pregnant women drank alcohol in the past month, and 20% to 30% drank at some point during the pregnancy. 3.6% of pregnant american women met criteria for an alcohol use disorder in a 2001 epidemiological study. the risk of fasd depends on the amount consumed, the frequency of consumption, and the points in pregnancy at which the alcohol is consumed. other risk factors include the mother's older age, smoking, and poor diet. there is no known safe amount or time to drink alcohol during pregnancy. although drinking small amounts does not cause facial abnormalities, it may cause behavioral problems. alcohol crosses the blood–brain barrier and both directly and indirectly affects a developing fetus. diagnosis is based on the signs and symptoms in the person. fetal alcohol spectrum disorders are preventable by the mother's avoiding alcohol during pregnancy. for this reason, medical authorities recommend that women completely avoid drinking alcohol during pregnancy and while trying to conceive. although the condition is permanent, treatment can improve outcomes. interventions may include parent–child interaction therapy, efforts to modify child behavior, and drugs. fasd is estimated to affect between 1% and 5% of people in the united states and western europe. fas is believed to occur in between 0.2 and 9 per 1,000 live births in the united states. in south africa, some populations have rates as high as 9%. the negative effects of alcohol during pregnancy have been described since ancient times. the lifetime cost per child with fas in the united states was estimated at $2 million (for an overall cost across the country of over $4 billion) by the cdc in 2002. however, a 2015 review article estimated the overall costs to canada from fasd at $9.7 billion (including from crime, healthcare, education, etc.). the term fetal alcohol syndrome was first used in 1973. types fetal alcohol spectrum disorders encompass a range of physical and neurodevelopmental problems which can result from prenatal alcohol exposure. the most severe condition is called fetal alcohol syndrome (fas), which refers to individuals who have a specific set of birth defects and neurodevelopmental disorders characteristic of the diagnosis. as of 2016, the swedish agency for health technology assessment and assessment of social services accepted only fas as a diagnosis, seeing the evidence as inconclusive with respect to other types. fetal alcohol syndrome (fas) partial fetal alcohol syndrome (pfas) refers to individuals with a known, or highly suspected, history of prenatal alcohol exposure who have alcohol-related physical and neurodevelopmental deficits that do not meet the full criteria for fas. pfas-subtypes: alcohol-related neurodevelopmental disorder (arnd) alcohol-related birth defects (arbd). neurobehavioral disorder associated with prenatal alcohol exposure (nd-pae) static encephalopathy there are conditions believed to be related to prenatal alcohol exposure, such as spontaneous abortion and sudden infant death syndrome (sids), which are also considered to be on the spectrum of related disorders. the swedish agency for health technology assessment and assessment of social services feels it is unclear as of 2016 if identifying a fasd-related condition benefits the individual. in 2013, the american psychiatric association introduced neurobehavioral disorder associated with prenatal alcohol exposure (nd-pae) into the dsm-v as a "condition for further study" and as a specified condition under, "other specified neurodevelopmental disorders" as a way to better study the behavioral aspects of all fasd disorders. though similar sounding, nd-pae is the spectrum-wide term for the psychiatric, behavioral, and neurological symptoms of all fasds, whereas arnd is the specific diagnosis of the non-dysmorphic type of fasd, where a majority of the symptoms are witnessed. signs and symptoms facial characteristics of a child with fas the key of fasd can vary between individuals exposed to alcohol during pregnancy. while consensus exists for the definition and diagnosis of fas, minor variations among the systems lead to differences in definitions and diagnostic cut-off criteria for other diagnoses across the fasd continuum. the central nervous system damage criteria particularly lacks clear consensus. a working knowledge of the key features is helpful in understanding fasd diagnoses and conditions, and each is reviewed with attention to similarities and differences across the four diagnostic systems. more than 400 problems, however, can occur with fasd. growth in terms of fasd, growth deficiency is defined as significantly below average height, weight or both due to prenatal alcohol exposure and can be assessed at any point in the lifespan. growth measurements must be adjusted for parental height, gestational age (for a premature infant), and other postnatal insults (e.g., poor nutrition), although birth height and weight are the preferred measurements. deficiencies are documented when height or weight falls at or below the 10th percentile of standardized growth charts appropriate to the population. prenatal or postnatal presentation of growth deficits can occur, but are most often postnatal. criteria for fasd are least specific in the institute of medicine (iom) diagnostic system ("low birth weight..., decelerating weight not due to nutrition..., disproportional low weight to height" p. 4 of executive summary), while the cdc use the 10th percentile as a cut-off to determine growth deficiency. the "4-digit diagnostic code" allows for mid-range gradations in growth deficiency (between the 3rd and 10th percentiles) and severe growth deficiency at or below the 3rd percentile. growth deficiency (at severe, moderate, or mild levels) contributes to diagnoses of fas and pfas, but not arnd or static encephalopathy. the "4-digit diagnostic code" from 2004 ranks growth deficiency as follows: severe: height and weight at or below the 3rd percentile. moderate: either height or weight at or below the 3rd percentile, but not both. mild: either height or weight or both between the 3rd and 10th percentiles. none: height and weight both above the 10th percentile. in the initial studies that described fas, growth deficiency was a requirement for inclusion in the studies; thus, all the original people with fas had growth deficiency as an artifact of sampling characteristics used to establish criteria for the syndrome. that is, growth deficiency is a key feature of fasd because growth deficiency was a criterion for inclusion in the study that defined fas. growth deficiency may be less critical for understanding the disabilities of fasd than the neurobehavioral sequelae to the brain damage. canadian guidelines updated in 2016 deleted growth as a diagnostic criterion. facial features smooth philtrum seen on a six-month-old baby with fas several characteristic craniofacial abnormalities are often visible in individuals with fas. the presence of fas facial features indicates brain damage, although brain damage may also exist in their absence. fas facial features (and most other visible, but non-diagnostic, deformities) are believed to be caused mainly during the 10th to 20th week of gestation. refinements in diagnostic criteria since 1975 have yielded three distinctive and diagnostically significant facial features which distinguish fas from other disorders with partially overlapping characteristics. the three fas facial features are: a smooth philtrum: the divot or groove between the nose and upper lip flattens with increased prenatal alcohol exposure. thin vermilion: the upper lip thins with increased prenatal alcohol exposure. small palpebral fissures: eye width decreases with increased prenatal alcohol exposure. measurement of fas facial features uses criteria developed by the university of washington. the lip and philtrum are measured by a trained physician with the lip-philtrum guide, a five-point likert scale with representative photographs of lip and philtrum combinations ranging from normal (ranked 1) to severe (ranked 5). palpebral fissure length (pfl) is measured in millimeters with either calipers or a clear ruler and then compared to a pfl growth chart, also developed by the university of washington. ranking fas facial features is complicated because the three separate facial features can be affected independently by prenatal alcohol. a summary of the criteria follows: severe: all three facial features ranked independently as severe (lip ranked at 4 or 5, philtrum ranked at 4 or 5, and pfl two or more standard deviations below average). moderate: two facial features ranked as severe and one feature ranked as moderate (lip or philtrum ranked at 3, or pfl between one and two standard deviations below average). mild: a mild ranking of fas facial features covers a broad range of facial feature combinations: two facial features ranked severe and one ranked within normal limits, one facial feature ranked severe and two ranked moderate, or one facial feature ranked severe, one ranked moderate and one ranked within normal limits. none: all three facial features ranked within normal limits. central nervous system central nervous system (cns) damage is the primary feature of any fasd diagnosis. prenatal alcohol exposure, which is classified as a teratogen, can damage the brain across a continuum of gross to subtle impairments, depending on the amount, timing, and frequency of the exposure as well as genetic predispositions of the fetus and mother. while functional abnormalities are the behavioral and cognitive expressions of the fasd disability, cns damage can be assessed in three areas: structural, neurological, and functional impairments. all four diagnostic systems allow for assessment of cns damage in these areas, but criteria vary. the iom system requires structural or neurological impairment for a diagnosis of fas, but also allows a "complex pattern" of functional anomalies for diagnosing pfas and arnd. the "4-digit diagnostic code" and cdc guidelines allow for a positive cns finding in any of the three areas for any fasd diagnosis, but functional anomalies must measure at two standard deviations or worse in three or more functional domains for a diagnosis of fas, pfas, and arnd. the "4-digit diagnostic code" also allows for an fasd diagnosis when only two functional domains are measured at two standard deviations or worse. the "4-digit diagnostic code" further elaborates the degree of cns damage according to four ranks: definite: structural impairments or neurological impairments for fas or static encephalopathy. probable: significant dysfunction of two standard deviations or worse in three or more functional domains. possible: mild to moderate dysfunction of two standard deviations or worse in one or two functional domains or by judgment of the clinical evaluation team that cns damage cannot be dismissed. unlikely: no evidence of cns damage. structural structural abnormalities of the brain are observable, physical damage to the brain or brain structures caused by prenatal alcohol exposure. structural impairments may include microcephaly (small head size) of two or more standard deviations below the average, or other abnormalities in brain structure (e.g., agenesis of the corpus callosum, cerebellar hypoplasia). microcephaly is determined by comparing head circumference (often