A new MRI study revealed that consumption of alcohol even in low to moderate amounts during pregnancy can change the baby’s brain structure and delay brain development. Results of the study will be presented next week at the annual meeting of the Radiological Society of North America (RSNA).
“Fetal MRI is a highly specialized and safe examination method that allows us to make accurate statements about brain maturation prenatally,” said study senior author Gregor Kasprian, M.D., associate professor of radiology from the Department of Biomedical Imaging and Image-guided Therapy of the Medical University of Vienna in Austria.
“Unfortunately, many pregnant women are unaware of the influence of alcohol on the fetus during pregnancy,” said lead author Patric Kienast, M.D., a Ph.D. student in the Department of Biomedical Imaging and Image-Guided Therapy, Division of Neuroradiology and Musculoskeletal Radiology at the Medical University of Vienna.
For the study, researchers analyzed MRI exams of 24 fetuses with prenatal alcohol exposure. The fetuses were between 22 and 36 weeks of gestation at the time of MRI. Alcohol exposure was determined via anonymous surveys of the mothers.
The questionnaires used were the Pregnancy Risk Assessment Monitoring System (PRAMS), a surveillance project of the Centers for Disease Control and Prevention and health departments, and the T-ACE Screening Tool, a measurement tool of four questions that identify risk drinking.
“We found the greatest changes in the temporal brain region and STS,” Dr. Kasprian said. “We know that this region, and specifically the formation of the STS, has a great influence on language development during childhood.”
Brain changes were seen in the fetuses even at low levels of alcohol exposure.
“Seventeen of 24 mothers drank alcohol relatively infrequently, with average alcohol consumption of less than one alcoholic drink per week,” Dr. Kienast said. “Nevertheless, we were able to detect significant changes in these fetuses based on prenatal MRI.”
Three mothers drank one to three drinks per week, and two mothers drank four to six drinks per week. One mother consumed an average of 14 or more drinks per week. Six mothers also reported at least one binge drinking event (exceeding four drinks on one occasion) during pregnancy.
According to the researchers, delayed fetal brain development could be specifically related to a delayed stage of myelination and less distinct gyrification in the frontal and occipital lobes.
The myelination process is critical to brain and nervous system function. Myelin protects nerve cells, allowing them to transmit information faster. Important developmental milestones in infants, as rolling over, crawling and language processing are directly linked to myelination.
“Pregnant women should strictly avoid alcohol consumption,” Dr. Kienast said. “As we show in our study, even low levels of alcohol consumption can lead to structural changes in brain development and delayed brain maturation.”
“To assess this accurately, we need to wait for the children who were examined as fetuses at that time to get a little older, so that we can invite them back for further examinations,” Dr. Kienast said. “However, we can strongly assume that the changes we discovered contribute to the cognitive and behavioral difficulties that may occur during childhood.”
Fetal and Neonatal Effects of Maternal Alcohol Consumption
It is challenging to assess a dose-response relationship between the quantity of alcohol consumed prenatally and the effect on fetal and neonatal outcomes. This difficulty stems from the variability in maternal alcohol clearance rates, fetal developmental sensitivity, genetic susceptibility, timing, and duration during pregnancy when alcohol is consumed, and other confounders such as polysubstance abuse or socioeconomic status. Although binge drinking may not be as concerning as chronic heavy alcohol consumption, adverse developmental effects in the fetus can still occur, especially depending on whether the drinking occurred during critical stages of organ formation.35 In addition, fetal alcohol metabolism is slower than in the mother so there may be higher levels of alcohol sustained longer in fetal blood than in maternal blood.15,16
STRUCTURAL IMPAIRMENTS
Prenatal alcohol exposure has been associated with multiple fetal structural anomalies including renal, cardiac, craniofacial, and other major malformations. Several characteristic craniofacial abnormalities include short palpebral fissures, a smooth philtrum, and a thin vermillion border of the upper lip.36,37 A previous prospective cohort study from Australia examined the association between prenatal alcohol exposure and the craniofacial shape of children at 12 months of age.12 Researchers followed and obtained information regarding alcohol consumption in 451 women 3 months before pregnancy and then each trimester with a subsequent 3-dimensional craniofacial assessment of children at 12 months of age.12 The study found that low-dose levels of prenatal alcohol can influence fetal craniofacial development but the clinical significance of this finding remains unknown.12
BIRTH OUTCOMES
Previous studies have noted that overall maternal alcohol consumption, including first-trimester or late-pregnancy use, can be associated with intrauterine growth restriction as well as an increased risk of stillbirth.14,38,39 However, the impact of maternal specifically low-dose alcohol consumption on birth outcomes is not well understood. Several previous systematic reviews found that it had little or no effect on intrauterine growth restriction, preterm labor, spontaneous abortion, or stillbirth.11,12
NEURODEVELOPMENTAL EFFECTS
It is unclear whether a single binge drinking episode in early gestation, during increased teratogen susceptibility, results in an increased fetal risk or impacts future child development. A previous prospective observational study, conducted over a decade, examined 51 preschool-aged offspring of nonalcohol-dependent women who engaged in 1 to 5 binge drinking episodes during the first trimester and compared them with 51 children not exposed to any teratogens.40 Depending on the child’s age, abilities and behavior in preschool offspring were assessed using validated scales. The study noted behavioral differences of pre-school-aged children within 3 of 9 scales, specifically a greater degree of disinhibited behavior but no differences in regards to physical, language, or cognitive outcomes.40
Although the association between chronic heavy alcohol consumption during pregnancy and adverse neurodevelopmental effects in childhood has been well studied, the effect of low-dose maternal drinking has been more difficult to elucidate. A previous large multinational systematic review from multiple countries, including the United States, England, and Australia, examined the cognitive, mental health, and socioemotional development of 3- to 16-year-old children following pregnancies with maternal low-dose alcohol consumption. The authors reported evidence of subtle long-term cognitive and behavioral effects such as inattention, mental health problems, and difficulties with short-term memory.41 A different study from Washington state followed children after low-moderate maternal alcohol consumption in pregnancy up to age 18 and found that half of the older children diagnosed with FAS exhibited normal developmental scores as pre-schoolers but by age 10 all had severe brain dysfunction (http://depts.washington.edu/fasdpn/).42 Only 10% of children diagnosed with FAS in this study had attention difficulties by age 5 but 60% were affected by age 10 and 100% had severe dysfunction in areas such as language, memory, and activity level (http://depts.washington.edu/fasdpn/).42
FASD
The FASD spectrum refers to a group of conditions that can occur in a person whose mother consumed alcohol during pregnancy and has lifelong implications (Fig. 1). Although the prevalence is difficult to assess, the CDC and other studies estimate 0.2 to 7 infants with FASD for every 1000 live births in certain areas of the United States.45,46 FAS is considered the most common teratogenically induced, nonhereditary form of mental deficiency throughout the western world. It is associated with reduced intelligence,47 attention disorders,48,49 neuropsychological deficits,50–53 physical abnormalities including facial dysmorphology,15,16 sleep disorders, and behavioral problems.
FIGURE 1.
Signs and symptoms of fetal alcohol syndrome disorder.43,44 IQ indicates intelligence quotient.
There is no cure for FASD and it is irreversible but it can be completely prevented if women abstain from alcohol consumption while pregnant or when trying to conceive given women often do not recognize they are pregnant until 4 to 6 weeks postconception.54,55
FAS
This represents the most involved end of the FASD spectrum. Those affected by FAS might have abnormal facial features, growth problems, central nervous system abnormalities, and difficulties with learning, memory, attention span, communication, vision, or hearing. Often, people with FAS have problems in school and trouble socially with others. The global prevalence of FAS in children and youth in the general population has been estimated to be 7.7 per 1000 population.56 A study aiming to identify the prevalence of FASD among first-grade students in a representative Midwestern US community estimated that FAS in that community likely ranged from 6 to 9 per 1000 children with the total rate of FASD likely ranging from 24 to 48 per 1000 children.57 This study also found that the most predictive maternal risk factors associated with the cognitive, behavioral, and neurodevelopmental effects seen in children with FASD are late recognition of pregnancy, the quantity of alcoholic drinks consumed 3 months before pregnancy and the quantity of drinking reported by the child’s father.
ALCOHOL-RELATED NEURODEVELOPMENTAL DISORDER
People with alcohol-related neurodevelopmental disorder can have intellectual disabilities and issues with behavior and learning. School is often challenging and they have difficulty with math, memory, attention, judgement, and poor impulse control.
ALCOHOL-RELATED BIRTH DEFECTS
Those with alcohol-related birth defect can have structural abnormalities of the heart, kidneys, and bones. They can also have complications with hearing.
Children With FASD
It is difficult to diagnose FASD because there is no biological test and other disorders such as attention-deficit/hyperactivity disorder and Williams syndrome have similar symptoms. Diagnosis includes evaluating for features of abnormal facial features, lower-than-average height and/or weight, central nervous system abnormalities (eg, small head circumference, problems with attention and hyperactivity, poor coordination) and prenatal alcohol exposure; although, confirmation of maternal alcohol consumptions is not required to diagnose FASD.
The prevalence of FASD in the United States has been noted to be as high as 1 to 5 per 100 school-aged children with FAS occurring in up to 6 to 9 of 1000 school-aged children.46,57–59 The cost to the United States for FAS alone, not including people with FASD, is over $4 billion annually with the lifetime cost of 1 individual with FAS of ~$2 million in 200246,57–59
Although FASD is irreversible, research has shown that early intervention services, from birth to 3 years of age, can improve a child’s development.60–62 These interventions include medications to ameliorate symptoms, behavior and education therapy, parent training, and other alternative approaches.60–62
Studies have also shown that some protective factors can help mitigate the adverse effects of FASD including diagnosis of FASD before the age of 6, a loving, nurturing, and stable home environment during school-age years, the absence of violence, and involvement in special education and social services.60–62 When children are diagnosed at a young age, they can then be placed in appropriate educational classes to receive appropriate social services that are geared to their specific needs and learning style. As children with FASD can be more sensitive to disruptions in lifestyle or routine, a stable home life can help prevent secondary conditions, such as criminal behavior, unemployment, and incomplete education that they are at increased risk for.
There is no specific medication approved for the treatment of FASD but there are different types of medications that can alleviate FASD symptoms including stimulants, antidepressants, neuroleptics, and anxiolytics.
NEUROBEHAVIORAL DISORDER ASSOCIATED WITH PRENATAL ALCOHOL EXPOSURE (ND-PAE)
ND-PAE refers to children exposed prenatally to alcohol that do not satisfy the full criteria for a diagnosis of FAS. This is a recognized condition in the Diagnostic and Statistical Manual 5 of the American Psychiatric Association since 2013. To meet criteria, the mother of the child must have consumed greater than minimal levels of alcohol, > 13 alcohol drinks per month or > 2 alcohol drinks in 1 sitting, prenatally. Children diagnosed with ND-PAE have difficulties in 3 areas: (1) thinking and memory; (2) behavior problems; and (3) trouble with day-to-day living. Problems in these areas can include problems with forgetting material learned, severe tantrums, irritable mood, difficulty shifting attention between tasks, playing with other children, and activities of daily living like bathing.
reference link : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7061927/#:~:text=Alcohol%20exposure%20during%20pregnancy%20results,some%20of%20these%20adverse%20outcomes.
Original Research: The findings will be presented at the 108th Scientific Assembly and Annual Meeting of the Radiological Society of North America
