Fetal alcohol spectrum disorders
Alcohol readily crosses the placenta and may disrupt fetal development.
Harm from prenatal alcohol exposure (PAE) is determined by the dose, pattern, timing and duration of exposure, fetal and maternal genetics, maternal nutrition, concurrent substance use, and epigenetic responses.
A safe dose of alcohol use during pregnancy has not been established.
Prenatal alcohol exposure can cause fetal alcohol spectrum disorders (FASD), which are characterized by neurodevelopmental impairment with or without facial dysmorphology, congenital anomalies and poor growth. FASD are a leading preventable cause of birth defects and developmental disability.
The prevalence of FASD in 76 countries is >1% and is high in individuals living in out-of-home care or engaged in justice and mental health systems.
The social and economic effects of FASD are profound, but the diagnosis is often missed or delayed and receives little public recognition.
Future research should be informed by people living with FASD and be guided by cultural context, seek consensus on diagnostic criteria and evidence-based treatments, and describe the pathophysiology and lifelong effects of FASD. Imperatives include reducing stigma, equitable access to services, improved quality of life for people with FASD and FASD prevention in future generations.
FASD occur in all socioeconomic and ethnic groups and are complex, chronic conditions that affect health and family functioning. Individuals with FASD usually require lifelong health care as well as social and vocational support. Some require remedial education and others interact with the justice system. Early diagnosis and a strength-based management approach will optimize health outcomes.
FASD are the most common of the potentially preventable conditions associated with birth anomalies and neurodevelopmental problems, and their global effects, including huge social and economic costs, are substantial.
For example, in Canada, the annual cost associated with FASD is an estimated ~CAD$ 1.8 billion which is attributable in part to productivity loss (41%), correction services (29%) and health care (10%).
In North America, the lifetime cost of supporting an individual with FASD is estimated at >CAD$ 1 million.
Addressing and preventing alcohol use in pregnancy is a public-health imperative.
This Primer presents the epidemiology of FASD and the latest understanding of its pathophysiology as well as approaches to diagnosis, screening and prevention. The Primer also describes outcomes across the lifespan, management and quality of life (QOL) of people living with FASD, and highlights important areas for future research and clinical practice.
Alcohol use during pregnancy
No safe level of prenatal alcohol exposure (PAE) has been established, and international guidelines advise against any amount or type of alcohol use during pregnancy.
Nevertheless, ~10% of pregnant women worldwide consume alcohol.
The highest prevalence of alcohol use during pregnancy is in the WHO European Region, consistent with the prevalence of heavy alcohol use, heavy episodic alcohol use and alcohol use disorders in this region.
The highest pooled prevalence (%) of alcohol use during pregnancy in the general population is estimated in the WHO European Region (25.2%), followed by the Region of the Americas (11.2%), the African Region (10.0%), the Western Pacific Region (8.6%) and the South-East Asia Region (1.8%), and the lowest prevalence is estimated in the Eastern Mediterranean Region (0.2%), where most of the population is of Muslim faith and the rates of abstinence from alcohol are very high. The pooled global prevalence of alcohol use during pregnancy in the general population is estimated at 9.8%.
In 40% of the 162 countries evaluated, >25% of women who consumed any alcohol during pregnancy consumed at ‘binge’ levels (defined as ≥4 US standard alcoholic drinks containing 14 g of pure alcohol per drink on a single occasion).
Binge alcohol use increases the risk of FASD. It is common in early pregnancy and before pregnancy recognition.
Risk factors for maternal alcohol consumption
Various risk factors have been identified for maternal alcohol use in pregnancy, including
- higher gravidity and parity,
- delayed pregnancy recognition,
- inadequate prenatal care or reluctance of health professionals to address alcohol use,
- a history of FASD in previous children,
- alcohol use disorder and other substance use (including tobacco),
- mental health disorders (such as depression),
- a history of physical or sexual abuse,
- social isolation (including living in a rural area during pregnancy),
- intimate partner violence,
- alcohol and/or other drug use during pregnancy by the mother’s partner, or other family members, and
Risk factors for alcohol use during pregnancy vary across countries and throughout the course of pregnancy.
For example, in Australia, first-trimester alcohol use was associated with unplanned pregnancy, age <18 years at first intoxication, frequent and binge alcohol use in adolescence, and current alcohol use and a tolerant attitude to alcohol use in pregnancy. Women who continued to consume alcohol throughout pregnancy were more likely to be older, have higher socioeconomic status, salary and educational levels, smoke, have a partner who consumes alcohol, and have an unintended pregnancy than those who abstained, and were less likely to agree with guidelines that recommend avoiding alcohol use in pregnancy.
Based on global epidemiological data, an estimated 1 in 13 women who consume alcohol while pregnant will deliver a child with FASD, resulting in the birth of ~630,000 children with FASD globally every year.
FASD confers lifelong disability, and an estimated >11 million individuals aged 0–18 years and 25 million aged 0–40 years have FASD.
A systematic review and meta-analysis revealed that FASD prevalence is 10–40 times higher in some subpopulations than in the general population, including in children in out-of-home care and correctional, special education, and specialized clinical settings.
The pooled prevalence of FASD among children in out-of-home or foster care is 25.2% in the USA and 31.2% in Chile (32-fold and 40-fold higher than the global prevalence, respectively).
- FASD prevalence among adults in the Canadian correctional system (14.7%) is 19-fold higher than in the general population.
- The FASD prevalence among special education populations in Chile (8.4%) is over 10-fold higher than in the general population.
- The prevalence of FASD is 62% among children with intellectual disabilities in care in Chile.
- The prevalence of FASD is 36% in one Australian youth correctional service, >23% in Canadian youth correctional services, >14% among USA populations in psychiatric care and 19% in some remote Australian Indigenous communities.
The high prevalence of FASD in some subpopulations has prompted calls for targeted screening in these groups.
Effects of prenatal alcohol exposure (PAE) on the embryo and fetus
PAE can affect brain development, brain structure, and craniofacial development.
PAE activates an inflammatory response in the developing nervous system.
PAE may cause enduring changes in the gut microbiota, and there is increasing recognition of the interplay between gut microbes and nervous system development and function.
Not all developmental effects of PAE result from the direct actions of alcohol on the developing nervous system. PAE in humans decreases placental weight, epigenetic marks, vasculature and metabolism.
Prevention and treatment of alcohol and other substance use disorders in pregnancy are central to the 2015 United Nations Sustainable Development Goals (SDG 3.5).
The WHO recommends universal screening and intervention for alcohol use in pregnancy as a primary prevention strategy for FASD.
Prevention programmes should be evidence based and evaluated following implementation. A wide range of approaches has been deployed, including public awareness strategies, preconception interventions (such as preconception clinics and school-based FASD education), holistic support of women with substance use disorders, and postpartum support for new mothers and babies.
These approaches show promise in increasing awareness of FASD and decreasing alcohol use during pregnancy; however, the quality of supporting evidence is highly variable.
Any primary prevention strategy must be underpinned by evidence-based policy and legislation intended to minimize harms from alcohol, including increased alcohol pricing and taxation, restrictions on advertising and promotion of alcohol, and restricted access to alcohol such as by limiting opening hours and the density of liquor outlets.
Public-health authorities agree that the alcohol industry should have no involvement in the development of public-health policies owing to their inherent conflict of interest. The framework in Fig. 7 illustrates one approach that could be linked to national policy to address diverse aspects of population-based prevention of FASD.
FASD are the most common preventable cause of neurodevelopmental impairment and congenital anomalies. These disorders are the legacy of readily available alcohol and societal tolerance to its widespread use, including during pregnancy. FASD affect all strata of society, with enormous personal, social and economic effects across the lifespan.