INTRODUCTION — Pregnant persons who drink alcohol come from all socioeconomic strata, ages, and races [1]. These individuals may also be using other addictive or illicit substances. Both the gravida and family benefit from factual, nonjudgmental information about the maternal and fetal risks of alcohol use and, if necessary, from counseling regarding strategies for cessation. Pregnant people are typically highly motivated to modify their behavior to help their unborn child. In one national survey from the United States, 87 percent of women who self-reported consumption of alcohol before pregnancy quit drinking during pregnancy, 6.6 percent reduced their alcohol intake, and approximately 6.4 percent reported no reduction [2].
This review will discuss issues regarding alcohol use in pregnancy, screening, and management. Related content on fetal alcohol spectrum disorder and use of other substances during pregnancy is presented separately.
●(See "Fetal alcohol spectrum disorder: Clinical features and diagnosis".)
●(See "Fetal alcohol spectrum disorder: Management and prognosis".)
●(See "Substance use during pregnancy: Screening and prenatal care".)
In this topic, when discussing study results, we will use the terms "woman/en" or "patient(s)" as they are used in the studies presented. We encourage the reader to consider the specific counseling and treatment needs of transgender and gender-expansive individuals.
EPIDEMIOLOGY OF ALCOHOL USE AND SCREENING
Alcohol consumption — Alcohol consumption during pregnancy is common [3]. The prevalence of alcohol consumption prior to and during pregnancy highlights the need to educate all reproductive age persons about the potential harms of alcohol exposure on the developing fetus.
●Rising prevalence in US population – Despite public education efforts, the percent of pregnant persons consuming alcohol in the United States steadily increased across four study periods (2006 to 2010, 2011 to 2013, 2015 to 2017, and 2018 to 2020) [3-6]. In the 2018 to 2020 survey by the Centers for Disease Control and Prevention (CDC), 5.2 percent of pregnant adults reported binge drinking within the prior 30 days and 13.5 percent reported current alcohol consumption, both of which are increased from prior surveys [3]. Although it is possible that the rising prevalence rates represented methodologic or other changes, this seems unlikely as the data were collected by the same organization (CDC) and used similar datasets (Behavioral Risk Factor Surveillance System).
●Increased prevalence with extension of study period – When the time period being studied is extended, pregnant persons report higher rates of alcohol use. The 2009 National Birth Defects Prevention Study of over 4000 patients that asked about drinking behavior for the entire duration of pregnancy found that 30 percent of pregnant persons reported any alcohol use and 8 percent reported binge drinking on at least one occasion [7]. Additionally, the 2004 Pregnancy Risk Assessment Monitoring System (PRAMS) survey that assessed preconception behavior determined that 50 percent of women self-reported alcohol use in the three months prior to pregnancy, which placed them at risk for an alcohol-exposed conception [7,8].
Screening during pregnancy — Although universal screening for alcohol use is advised [9,10], evidence suggests that screening remains suboptimal [11]. Analysis of 2017 and 2019 US Behavioral Risk Factor Surveillance Systems (BRFSS) data revealed that while approximately 80 percent of pregnant patients reported being asked about alcohol consumption at their most recent care visit, only 16 percent who reported alcohol consumption were advised to stop or reduce their alcohol use [11]. In addition, screening for alcohol use occurred less frequently in pregnant patients who had not graduated from high school compared with those who had (53.5 versus 83.4 percent screened for alcohol use in past two years). This data supports the need for continued clinician education about universal substance screening and follow-up.
SAFE LEVEL OF ALCOHOL INTAKE — A safe level of alcohol consumption during pregnancy has not been determined. Thus, multiple medical societies advise against alcohol use during pregnancy [12-14]. Assessing the impact of alcohol on fetal development is challenging because of variations in maternal alcohol clearance rates, fetal developmental sensitivity, genetic susceptibility, drinking pattern (eg, binge versus daily consumption), and confounders such as use of other substances. As alcohol is a teratogen that impacts fetal growth and development at all stages of pregnancy, national guidelines and medical societies from multiple countries recommend complete abstinence during pregnancy [9,15-19]. Abstaining from alcohol while pregnant eliminates the risk of alcohol-related congenital anomalies and developmental disabilities, including resultant neurocognitive and behavioral problems [15]. Use of a free online infographic may help convey these concerns to patients.
There is no exact dose-response relationship between the amount of alcohol consumed during the prenatal period and the extent of damage caused by alcohol in the infant. Infants whose mothers consume alcohol during pregnancy can manifest fetal alcohol effects (FAE), alcohol-related birth defects (ARBD), fetal alcohol syndrome (FAS), or they may be normal [20]. The term fetal alcohol spectrum disorder (FASD) has been coined to describe the broad range of adverse sequelae in alcohol exposed offspring [21]. A 2018 study of over 6600 United States first grade students from four different communities reported conservative estimates of FASD that ranged from 1.1 to 5.0 percent [22]. FAS represents the most severe sequelae of fetal alcohol exposure; however, there is a continuum of outcomes associated with prenatal exposure to alcohol that varies by parameter being studied.
●Structural development – A prospective cohort study obtained detailed information about self-reported alcohol consumed three months before pregnancy and for each trimester, including the time prior to pregnancy recognition, from 415 White patients in Australia [23]. The researchers then assessed three-dimensional craniofacial images of 415 children taken at 12 months of age. Results from this study, which relied on maternal self-report of alcohol use [24], suggest that low levels of prenatal alcohol use can influence craniofacial development of the fetus. However, the clinical significance of these findings remains to be determined.
●Birth outcomes – Although a systematic review did not find a significant increase in risk of low birth weight or birth of a small for gestational age infant for alcohol intake up to 10 g pure alcohol/day (approximately one drink per day) or an increase in preterm birth for alcohol intake up to 18 g pure alcohol/day (approximately 1.5 drinks per day), the risk of these outcomes progressively increased and became statistically significant with greater alcohol consumption [25]. This review did not evaluate the risk of alcohol-related fetal damage (FAE, ARBD, FAS, FASD), which is an important limitation to the conclusions of the meta-analysis. Furthermore, the studies included in the meta-analysis relied on self-reports of alcohol consumption and did not take patterns of alcohol use into account. As such, it did not provide definitive information about the risks associated with light to moderate prenatal alcohol.
●Neurodevelopmental outcomes – Available data conflict regarding the neurodevelopmental impact of alcohol consumption during pregnancy. This likely reflects the complex interaction of gestational age, dose and duration of alcohol exposure, underlying variations in maternal alcohol metabolism, and duration of study follow-up. Examples of studies evaluating this question, and their limitations, include:
•A series of studies from Denmark that evaluated the effects of maternal self-report of low to moderate alcohol consumption (<9 drinks/week) in early to mid-pregnancy on developmental outcomes (IQ, attention, executive function, motor function, behavior) in 5-year-old children did not find significant effects [26-31]. However, there are several limitations to these data. The Danish studies did not conduct FAS diagnostic evaluations and they assessed only preschoolers, which can be misleading because these children were too young to for the full impact alcohol may have had on their brains to be measured.
•On the other hand, a large well-designed study from Washington state that followed children up to age 18 demonstrated the importance of longitudinal follow-up in ascertaining the effects of prenatal alcohol exposure [32]. Specific findings included that although half of older children with FAS exhibited normal developmental scores as preschoolers, all had severe brain dysfunction confirmed by age 10; only 10 percent of children with FAS had attention problems by age 5 but 60 percent had attention problems by the age of 10; and only 30 percent of children with FAS had an IQ below normal, but 100 percent had severe dysfunction in other areas such as language, memory and activity level, which the Danish study did not assess [33].
Patterns of maternal alcohol consumption and socioeconomic and ethnic factors also affect outcome. As an example, binge drinking may exert a potentially greater negative effect than comparable consumption of low amounts of alcohol over several days (eg, four drinks in one sitting versus one drink a day for four days) [34-36], but this is also controversial [26-30]. Affluent pregnant persons tend to be better educated and have access to resources that may be less available to less affluent pregnant persons; these resources may confound conclusions by overcoming some of alcohol's negative impact on childhood development [37].
For unknown reasons, older maternal age, high parity, and African-American or Native American ethnicities appear to increase the risk of FAS. Other characteristics associated with those at higher risk for having an alcohol exposed pregnancy include low socioeconomic status, smoking, unmarried, unemployed, use of illicit drugs, history of sexual or physical abuse or neglect, history of incarceration, having a partner or family member who drinks heavily, being socially transient, and having psychologic stress or a mental health disorder [38,39].
Alcohol freely crosses the placenta: fetal blood alcohol levels approach maternal levels within two hours of maternal intake. Elimination of alcohol relies primarily on maternal metabolic capacity, which varies widely among pregnant individuals and may help explain why similar amounts of ethanol consumption result in widely varying phenotypic presentations in infants [40]. Polymorphisms of the alcohol dehydrogenase gene could explain variations in blood alcohol levels among individuals ingesting the same amount of ethanol. Maternal, and possibly fetal, polymorphisms of the gene ADH1B appear to contribute to FASD susceptibility [41]. It is hypothesized that the gene affects peak blood alcohol levels that, in turn, correlate with the risk of adverse fetal effects [41-43]. ADH1B polymorphisms may affect alcohol levels by affecting alcohol metabolism [44]. Expression of the cytochrome P450 E1 (CYP2E1) gene also affects alcohol metabolism and may play a role in vulnerability to FAS.
PERINATAL OUTCOMES — Alcohol is a teratogen with the potential to cause deleterious effects at all stages of gestation. The effects vary depending upon the quantity and pattern of alcohol consumption, maternal and fetal genetics, maternal age, maternal nutrition, and smoking, among other factors. The most severe consequences of prenatal alcohol exposure are stillbirth and fetal alcohol spectrum disorder (FASD), which encompasses the physical, mental, behavioral, and cognitive effects associated with in utero alcohol exposure. In two large epidemiologic studies, an increased rate of stillbirth was noted across all categories of alcohol intake, even after adjusting for confounders (eg, smoking, prepregnancy weight) [45,46]. The rate of death from fetoplacental dysfunction rose from 1.37 per 1000 births for patients consuming less than one drink per week to 8.83 per 1000 births for those consuming greater than or equal to five drinks per week. The clinical features, diagnosis, management, and prognosis of FASD are reviewed separately. (See "Fetal alcohol spectrum disorder: Clinical features and diagnosis" and "Fetal alcohol spectrum disorder: Management and prognosis".)
There is continuing uncertainty about the effects of low and low-to-moderate levels of alcohol intake in pregnancy. Although several studies have not found adverse behavioral and developmental effects, these studies have several methodologic limitations [20,47-50]. As discussed above, a prospective cohort study of data collected from 2011 to 2014 reported craniofacial changes with almost any level of prenatal alcohol intake, but clinical significance of these changes is not known [23]. A different prospective cohort study (data from 2000 to 2020) of over 5300 urban United States patients reported that alcohol use during weeks 5 through 10 (from last menstrual period) was associated with increased risk of early pregnancy loss, with peak risk in week 9 [51]. Each successive week of alcohol consumption resulted in an 8 percent increase in risk of pregnancy loss compared with nonusers, and the risk was cumulative. In this study, risk of pregnancy loss was not related to number of drinks per week, type of alcohol consumed, or binge drinking. A different retrospective study of 9700 youths ages 9.0 to 10.9 years reported any degree of prenatal alcohol exposure was associated with greater psychopathology, attention deficits, and impulsiveness [52].
Higher quality studies related to this type of drinking are needed. Hence, there is no confirmed "safe" threshold of alcohol exposure during pregnancy so avoiding alcohol may be the most prudent approach. (See 'Safe level of alcohol intake' above.)
SCREENING FOR ALCOHOL MISUSE
Rationale — Consistent screening for alcohol use followed by education, assessment, and treatment referral, if indicated, are effective and will help to ensure the best possible outcome for all pregnant persons and their babies [53,54]. Linking substance use disorder treatment with prenatal care has a positive effect on maternal and newborn health [55]. Maternal cessation of alcohol intake at any point during pregnancy is beneficial as children born to individuals who stop drinking even late in gestation have better outcomes than those born to individuals who continue to drink throughout pregnancy [56].
History — All pregnant persons should be screened for use of licit and illicit substances [9,57]. Many screening options are possible, from self-administered questionnaires to analysis of biological samples taken from the pregnant woman or her offspring. A practical, effective approach is to interview each woman with respectful and sensitive use of neutrally worded questions. It is preferable to begin by asking about lawful substances, such as cigarette smoking and alcohol, followed by questions about illicit drugs.
The typical questions asked about the quantity and frequency of alcohol use are less helpful in the assessment of prenatal alcohol consumption than in other populations. This discordancy is due to modification of alcohol consumption once pregnancy is recognized and the fact that traditional alcohol screening measures were developed in males with alcohol use disorders [58]. In addition, admission of alcohol use during pregnancy can be stigmatizing; thus, pregnant individuals may be reluctant to admit to any amount of drinking.
Clinicians can choose screening strategies that are appropriate for their clinical population and setting. T-ACE, TWEAK, and AUDIT-C are brief alcohol screening questionnaires used to identify problem drinking in pregnant persons. In a systematic review of these instruments and others (CAGE, SMAST), at-risk drinking sensitivity was highest for T-ACE (69 to 88 percent), TWEAK (71 to 91 percent), and AUDIT-C (95 percent), with high specificity (71 to 89 percent, 73 to 83 percent, and 85 percent, respectively) [59]. CAGE and SMAST performed poorly. Sensitivity of AUDIT-C at score ≥3 was 100 percent for past year DSM-IV alcohol dependence and 90 percent for alcohol use disorder, with moderate specificity (71 percent for each).
T-ACE — The T-ACE is a simple screening instrument for alcohol use designed specifically for the prenatal setting [60]. It identifies a range of alcohol consumption from any current prenatal drinking, prepregnancy risk drinking defined as more than two drinks per drinking day, to lifetime alcohol diagnoses based on the Diagnostic and Statistical Manual of Mental Disorders [61]. The T-ACE questions are:
●How many drinks does it take for you to feel high (TOLERANCE)?
●Do you feel ANNOYED by people complaining about your drinking?
●Have you ever felt the need to CUT down on your drinking?
●Have you ever had a drink first thing in the morning (EYE-OPENER)?
One point is given for each affirmative answer to the Annoy, Cut-down, and Eye-opener questions; 2 points are allotted if a woman reports tolerance to more than two drinks. A score of 2 or more is a positive score. The overall sensitivity (ie, the probability that a woman who is a risk drinker scores positive) of T-ACE is 69 percent, with specificity of 85 percent [60].
TWEAK — TWEAK is another screening instrument used in pregnant persons:
●T = TOLERANCE for alcohol
●W = WORRY or concern by family or friends about drinking behavior
●E = EYE OPENER, the need to have a drink in the morning
●A = "blackouts" or AMNESIA while drinking
●K = the self-perception of the need to CUT DOWN on alcohol use
Scores range from 0 to 7. The tolerance and worry questions each contribute 2 points and the other three questions contribute 1 point each. Any endorsement of the worry question is scored a 2; on the tolerance question, if three or more drinks are needed to feel high, the question is scored as a 2. Other versions of the TOLERANCE question ask:
●How many drinks does it take before the alcohol makes you fall asleep or pass out?
●If you never drink till you pass out, what is the largest number of drinks you have or can hold?
If the woman answers "five or more drinks," these questions are given a score of 2 points.
A total score of ≥3 on the TWEAK is suggestive of heavy drinking patterns [62-64]. However, both the TWEAK and TACE tests can miss light drinking, and sensitivity varies by ethnic group [63].
AUDIT-C — A third option for a brief screening questionnaire is the AUDIT-C. In this system, a total score of ≥3 points is positive for women.
●How often have you had a drink containing alcohol in the past year?
•Never: 0 points
•Monthly or less: 1 point
•Two to four times a month: 2 points
•Three times a week: 3 points
•Four times or more per week: 4 points
●How many drinks did you have on a typical day when you were drinking in the past year?
•One or two: 0 points
•Three or four: 1 point
•Five or six: 2 points
•Seven to nine: 3 points
•10 or more: 4 points
●How often did you have six or more drinks on one occasion during the past year?
•Never: 0 points
•Monthly or less: 1 point
•Monthly: 2 points
•Weekly: 3 points
•Daily or almost daily: 4 points
An in-depth discussion of screening and diagnosis of individuals with alcohol problems can be found separately. (See "Screening for unhealthy use of alcohol and other drugs in primary care", section on 'Special populations'.)
Laboratory testing — The reference standard in detecting alcohol fetal exposure is maternal self-report [65]. Recent alcohol intake is evaluated by measuring the blood alcohol level; this level can be estimated by breathalyzer. However, individual variability in ethanol pharmacokinetics makes interpretation of alcohol levels challenging. Chronic alcohol consumption may be suspected based upon abnormalities of liver function tests, macrocytosis, anemia, or carbohydrate-deficient transferrin (which is affected by pregnancy).
Hence, the use of biomarkers for prenatal alcohol exposure has been proposed as an adjunct for both research and clinical purposes [65]. Although there is no agreement among research groups concerning the best method for analyzing biological samples or when these tests should be used in pregnant individuals, several biomarkers have been suggested. These include phosphatidyl ethanol (PEth), fatty acid ethyl esters (FAEEs), and ethyl glucuronide (EtG).
PEth has a long half-life and is measurable for up to six weeks after intake; a blood sample is required [66]. FAEEs are a direct biomarker of alcohol that persists in blood for at least 24 hours after the last alcohol intake and can also be detected in maternal hair and neonatal meconium [65,67]. EtG is a very sensitive and specific biomarker of alcohol exposure because it is detectable only if alcohol has been consumed. EtG can be found in serum or urine but has a low incorporation rate in hair. EtG is detectable in urine specimens one hour after alcohol intake and up to five days later [68].
There are many limitations to widespread utilization of biomarkers. These include the need to identify the optimal combination of self-report and the biomarkers themselves. Patient acceptability and cost of these analyses may limit widespread implementation. (See "Screening for unhealthy use of alcohol and other drugs in primary care", section on 'Special populations'.)
Positive tests can have legal and economic implications. Patients should give informed consent prior to laboratory testing; random testing is unethical [69-71]. Medically indicated alcohol testing without written consent is acceptable in individuals who are unconscious or show obvious signs of intoxication and need to be tested to provide the appropriate medical interventions. Clinicians should be aware of their state's requirements for testing and reporting drug test results.
MANAGEMENT OF SCREEN-POSITIVE PREGNANT PERSONS — A positive screen provides an opportunity to proceed with a careful, nonjudgmental assessment of the patient's current and past alcohol consumption. This focus on drinking behavior can be beneficial, as the assessment of alcohol intake itself and the counseling and support provided by a nonjudgmental clinician can motivate some patients to abstain.
●Supporting data – A meta-analysis of randomized trials comparing psychosocial interventions aimed at stopping or reducing alcohol intake during pregnancy with usual care reported psychosocial intervention increased continuous abstinence (687 versus 513 per 1000 patients, risk ratio 1.34, 95% CI 1.14-1.57, 3 trials, n = 378 participants) [72]. Psychosocial interventions, which included educational sessions, motivational enhancement therapy, self-help groups, psychotherapeutic techniques, and cognitive behavioral interventions, were delivered in 10- to 60-minute sessions over one to five sittings [72,73]. Clinicians caring for pregnant persons are encouraged to continue routine education and offer access to psychosocial interventions, where available. Even if additional support is not available, brief intervention aimed at reducing alcohol consumption is more effective than no intervention [74-79]. Conversely, pregnancy-specific policies focused on reducing alcohol use during pregnancy, such as US state-level reporting requirements for suspicion or evidence of alcohol use during pregnancy, have not been associated with reduced harm to infants [80].
●Additional benefits – Reported benefits of intervention include reduced alcohol consumption [78,79], reduced risk for an alcohol-exposed pregnancy [74], higher rates of abstinence [75], and improvement in fetal and newborn outcomes [75]. In one randomized trial, including a partner chosen by the patient during treatment led to greater reduction in alcohol use, particularly among heavy drinkers [78].
●Identification of alcohol use disorder – Some individuals with alcohol use disorder require referral for in-depth counseling and treatment regimens. Patients identified to have heavy drinking patterns and who are unlikely to reduce their consumption should be referred to professional alcohol treatment. (See "Alcohol use disorder: Treatment overview" and "Alcohol use disorder: Psychosocial management".)
PREGNANCY MANAGEMENT — Comprehensive prenatal care can ameliorate some of the maternal and neonatal complications of maternal substance use. The components of this care include [69]:
●Screening of all pregnant persons for alcohol use.
●Counseling regarding the risks of alcohol use.
●Assembling a multidisciplinary team of health care and social service providers to comprehensively assess gravidas who use alcohol and their offspring.
●Scheduling frequent prenatal visits to monitor maternal and fetal status and provide education and support.
●Obtaining an early ultrasound examination to confirm gestational age and establish an accurate baseline for following fetal growth.
●Beginning antepartum fetal surveillance if there is evidence of pregnancy complications (eg, growth restriction, third trimester bleeding, maternal withdrawal).
●Informing the pediatrician of the possibility of neonatal withdrawal.
●Discouraging breastfeeding in individuals who continue to consume alcohol.
RESOURCES FOR PATIENTS AND CLINICIANS
●The American College of Obstetricians and Gynecologists (ACOG) offers an online Frequently Asked Questions infographic on "Alcohol and Pregnancy" that is available for free in both English and Spanish.
●The US Centers for Disease Control and Prevention (CDC) offers free communication materials for health care providers and patients on alcohol and pregnancy, including their "Let’s Talk" communication aid.
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Alcohol consumption" and "Society guideline links: Substance misuse in pregnancy" and "Society guideline links: Fetal alcohol spectrum disorder".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topic (see "Patient education: Alcohol and drug use in pregnancy (The Basics)" and "Patient education: Fetal alcohol syndrome (The Basics)")
SUMMARY AND RECOMMENDATIONS
●Alcohol use in pregnancy is common – More than one-half of all females of childbearing age (18 to 44 years of age) report alcohol use, and one in eight report binge drinking in the past month. (See 'Epidemiology of alcohol use and screening' above.)
●Negative effects of prenatal alcohol consumption – Alcohol consumption appears to have negative effects throughout pregnancy, including teratogenic effects and increased risk of pregnancy loss. (See 'Perinatal outcomes' above.)
●Lack of dose-response relationship – There is no exact dose-response relationship between the amount of alcohol consumed during the prenatal period and the extent of damage caused by alcohol in the infant. We recommend abstinence from alcohol at conception and during pregnancy (Grade 1C). (See 'Safe level of alcohol intake' above.)
●Screening for alcohol use during pregnancy – Identification and counseling of pregnant persons who use alcohol can decrease intake during pregnancy. Given that alcohol is a known teratogen and a safe level of intake during pregnancy has not been established, we recommend screening all pregnant individuals for any use of alcohol (Grade 1B). (See 'Screening for alcohol misuse' above and 'Management of screen-positive pregnant persons' above.)
●Screening tools – The T-ACE, TWEAK, or AUDIT-C screening tool can be used to identify individuals who may be at risk for prenatal alcohol use. Clinicians should choose a screening strategy that is appropriate for their clinical population and setting. (See 'Screening for alcohol misuse' above.)
●Intervention options – For pregnant persons who consume alcohol but are not heavy drinkers, we recommend a brief intervention (eg, educational session(s), motivational counseling) rather than no intervention or more extensive alcohol cessation programs (Grade 1A). Individuals with heavy drinking patterns who are unlikely to reduce their consumption should be referred to professional alcohol treatment. (See 'Management of screen-positive pregnant persons' above.)
Do you want to add Medilib to your home screen?