Intrauterine exposure to alcohol and tobacco use and childhood IQ: findings from a parental-offspring comparison within the Avon Longitudinal Study of Parents and Children

Low to Moderate Prenatal Alcohol Exposure and Neurodevelopmental Outcomes: A Narrative Review and Methodological Considerations

PURPOSE

Although abstinence is recommended in pregnancy, many pregnancies are exposed to alcohol. Observational studies of the effects of low to moderate prenatal alcohol exposure (PAE) and neurodevelopmental outcomes have yielded inconsistent results, with some studies finding an increased risk of adverse neurobehavioral and cognitive outcomes, and other studies finding no changes or reduced risk of the same outcomes. The purpose of this narrative review is to summarize these inconsistencies and apply a methodological framework to discuss how different parameters contribute to the findings. The authors also provide recommendations on how to advance future research in this area.

SEARCH METHODS

The PubMed, Web of Science, and Embase databases were searched, along with reference lists of selected systematic reviews and meta-analyses. Search terms used were (infant or child or children or adolescent or offspring) AND (low or light or mild or moderate or low-to-moderate) AND (drinking or alcohol or drinks) AND (pregnancy or prenatal or fetal) AND (neurodevelopment or behavioral or psychological or cognitive or developmental) NOT (mice or rat or fish or animal) NOT (meta-analysis or review). Peer-reviewed original research studies were included if they analyzed associations between an exposure defined and characterized as low/light or moderate PAE with offspring neurodevelopmental outcomes. Animal studies, studies that did not provide clear cutoff points to classify PAE categories, studies lacking an abstinence control group, and studies that did not present a multivariable-adjusted measure of association were excluded.

SEARCH RESULTS

The searches identified 2,422 papers, with 36 papers meeting eligibility criteria. These studies were carried out across nine countries and included samples ranging from approximately 500 to 40,000 participants. Cognitive, academic, socioemotional, and behavioral outcomes were assessed from infancy through age 19.

DISCUSSION AND CONCLUSION

When the findings from the selected articles were summarized by geographic region, exposure definition, or neurodevelopmental outcome, no consistent observations or patterns emerged between low to moderate PAE and offspring outcomes. Although some studies found positive (i.e., beneficial) associations between low to moderate PAE and outcomes (primarily outcomes related to cognition) and others found negative (i.e., detrimental) associations (primarily for behavioral outcomes), most findings were null (i.e., showed no effect of PAE). The heterogeneity in study results is likely due to methodological issues, including residual confounding, effect measure modification, and exposure misclassification that make synthesis of studies difficult. Alternative study designs, including longitudinal trajectory analysis, sibling design, negative controls, and instrumental variable analyses, may reduce biases and are discussed. To date, the consequences of light to moderate levels of PAE on neurodevelopment remain unresolved; studies that advance methodological rigor will be important contributions to the field.

Impact of prenatal alcohol exposure on neurodevelopmental outcomes: a systematic review

Background

Prenatal exposure to alcohol (PAE) represents a significant public health concern. Previous research linking PAE to neurodevelopmental outcomes has been mixed and often has limited focus on residual confounding or moderating factors.

Methods

A systematic review of prospective cohort studies (n = >1000) assessing the impact of PAE on neurodevelopmental outcomes was undertaken (neurophysiology, motor skills, cognition, language, academic achievement, memory, attention, executive function, affect regulation, and adaptive behaviour, social skills, or communication). Electronic searches of EMBASE, Medline, CINAHL, and Psychinfo were conducted in May 2021. A quality assessment was conducted using an adapted version of the Newcastle-Ottawa Scale (NOS).

Results

Thirty longitudinal cohort studies met the inclusion criteria. Evidence of the impact of PAE was mixed across domains. We found no evidence that PAE affects executive function, but there were impacts on motor skills, cognition, language, academic achievement, attention, affect regulation, and adaptive behaviour. The most consistent adverse effect was on affect regulation (nine out of thirteen studies, six of which found an association between heavy alcohol consumption or binge drinking during pregnancy). We found no protective factors. Few studies controlled for variables in the postnatal environment.

Discussion

This review was unable to conclude a safe level of alcohol consumption during pregnancy. Methodological improvements are needed to improve the quality and consistency in which PAE is studied. Further research into residual confounding variables is vital, including a greater focus on the postpartum environment.

Maternal smoking during pregnancy and intelligence quotient of offspring aged 18 and 30 years: Evidence from two birth cohorts in southern Brazil

Maternal smoking during pregnancy causes several harmful effects, including deficits in the intelligence quotient (IQ), a measure associated with academic achievements and higher socioeconomic position. We aimed to measure the association between maternal smoking during pregnancy and offspring's IQ in two birth cohorts from Pelotas, Brazil. Data from the 1982 and 1993 birth cohorts were analyzed. Smoking during pregnancy was ascertained at the perinatal follow-up, and IQ was measured at 30 years (1982) and 18 years (1993). Simple and multiple linear regressions were used for crude and adjusted analysis. Mediation analysis was performed using birth weight and breastfeeding as possible mediators. Data analysis was conducted in 2020. There were 3611 and 4050 participants from the 1982 and 1993 cohorts, respectively. After adjustment for potential confounders, the inverse association between smoking during pregnancy and children's IQ remained significant in both cohorts. Offspring of mothers who smoked during pregnancy had an average of 1.32 less IQ points (95%CI: -2.23, -0.242) in the 1982 cohort, and an average of 1.66 less IQ points (95%CI: -2.42, -0.90) in the 1993 cohort. Neither cohort showed association with paternal smoking (negative controls) after adjustment. Breastfeeding's mediated effects accounted for 26.2% and 23.9% of the association in the 1982 and 1993 cohorts, respectively, while birth weight's accounted for 6.8% and 30.1%, respectively; indirect effects were not significant. The inverse association between maternal smoking and IQ and the lack of association with paternal smoking reinforces our findings of a negative association between exposure and outcome.

Perinatal, neonatal, developmental and demographic predictors of intelligence at 4 years of age among low birth weight children: a panel study with a 2-year follow-up

Intoduction

Childhood intelligence is an important predictor of later outcomes in life such as socioeconomic status or health. Hence, a deeper understanding of predictors of child intelligence should suggest points of intervention for children facing adversities.

Objectives

The purpose of this study is to examine the predictive value of demographic, perinatal and neonatal variables after birth and developmental characteristics at age 2 for 4-year intelligence as outcome among low birth weight children.

Methods

We designed a panel study with a 2-year follow-up with 114 child-mother pairs. The outcome variable was IQ intelligence quotient at 4 years of age of LBW low birth weight children measured by the Wechsler Primary and Preschool Scales of Intelligence. Potential predictors were maternal education, family wealth, ethnic identity; sex, twin pregnancy, gestational age, birth weight, Apgar scores, maternal smoking during pregnancy; diagnosis of intravetricular haemorrhage, retinopathy of prematurity, bronchopulmonary dysplasia after birth and cognitive, language and motor development at age 2 measured by one composite score of the three Bayley Scales of Infant and Toddler Development aggregated.

Results

Stepwise backward regression was carried out including significant variables from the bivariate analysis. The best model included 4 predictors which accounted for 57% of the variance of the full IQ intelligence at 4-years of age. Maternal higher education was significant positive, below average family wealth and neonatal diagnosis of bronchopulmonary dysplasia were significant negative predictors in the model after birth. 2-year developmental characteristics such as cognitive, motor and language skills were positive predictors of the IQ intelligence at age 4.

Conclusion

Sociodemographic assessment at birth and developmental assessment at two years of age are of crucial importance to recognize children at high risk for delayed cognitive development. High-risk children should be directed to supportive interventions and their development should be regulary monitored.

Maternal smoking during pregnancy and intelligence quotient in offspring: A systematic review and meta-analysis

BACKGROUND

Exposure to tobacco during pregnancy may disrupt fetal brain development and impact offspring cognitive development.

AIMS

To perform a systematic review and meta-analysis on maternal smoking during pregnancy and intelligence quotient (IQ) in childhood, adolescence, and adulthood.

METHODS

We searched PubMed, Lilacs, PsycINFO, and Web of Science. Original articles evaluating tobacco use/exposure during pregnancy and the offspring's IQ as the outcome. The review protocol is registered in PROSPERO (number CRD 42,019,116,257). For the meta-analysis, we included studies with information on the regression coefficient and its confidence interval (CI) or standard error. Random effects model was used for pooling the estimates.

RESULTS

25 studies were included in the review, and of these 14 met the inclusion criteria for the meta-analysis. The overall pooled estimate showed that subjects who were exposed to maternal smoking during pregnancy presented lower IQ scores, compared to those not exposed to maternal smoking (β -1.30; 95 % CI -1.74, -0.86; I² = 87.8 %); IQ scores were also lower in crude (β -5.46; 95 % CI -7.31, -3.60; I²: 79.0 %) and adjusted pooled estimates (β =-0.45; 95 % CI -0.76, -0.13; I² = 80.4 %), for the group exposed to maternal smoking. In the stratified analysis, an inverse association was also observed in studies with large sample size (n≥1000 participants) (β=-0.49; 95 % CI -0.96, -0.02), among those performed with adolescents (β=-1.16; 95 % CI -2.18, -0.14), and among those adjusted for maternal education (β=-0.57; 95 % CI -1.05, -0.08).

CONCLUSIONS

Our findings suggest that exposure to tobacco during pregnancy may have negative effects on IQ. However, the findings of this meta-analysis should be interpreted with caution.

Evidence of detrimental effects of prenatal alcohol exposure on offspring birthweight and neurodevelopment from a systematic review of quasi-experimental studies

BACKGROUND

Systematic reviews of prenatal alcohol exposure effects generally only include conventional observational studies. However, estimates from such studies are prone to confounding and other biases.

OBJECTIVES

To systematically review the evidence on the effects of prenatal alcohol exposure from randomized controlled trials (RCTs) and observational designs using alternative analytical approaches to improve causal inference.

SEARCH STRATEGY

Medline, Embase, Web of Science, PsychINFO from inception to 21 June 2018. Manual searches of reference lists of retrieved papers.

SELECTION CRITERIA

RCTs of interventions to stop/reduce drinking in pregnancy and observational studies using alternative analytical methods (quasi-experimental studies e.g. Mendelian randomization and natural experiments, negative control comparisons) to determine the causal effects of prenatal alcohol exposure on pregnancy and longer-term offspring outcomes in human studies.

DATA COLLECTION AND ANALYSIS

One reviewer extracted data and another checked extracted data. Risk of bias was assessed using customized risk of bias tools. A narrative synthesis of findings was carried out and a meta-analysis for one outcome.

MAIN RESULTS

Twenty-three studies were included, representing five types of study design, including 1 RCT, 9 Mendelian randomization and 7 natural experiment studies, and reporting on over 30 outcomes. One study design-outcome combination included enough independent results to meta-analyse. Based on evidence from several studies, we found a likely causal detrimental role of prenatal alcohol exposure on cognitive outcomes, and weaker evidence for a role in low birthweight.

CONCLUSION

None of the included studies was judged to be at low risk of bias in all domains, results should therefore be interpreted with caution.

SYSTEMATIC REVIEW REGISTRATION

This study is registered with PROSPERO, registration number CRD42015015941.

The effect of confounding variables in studies of lead exposure and IQ

Methods proposed to address confounding variables frequently do not adequately distinguish confounding from covariation. A confounder is a variable that correlates both with the outcome and the major exposure variable. Accurate treatment of confounding is crucial to low dose extrapolation of the effects of chemical exposures based on epidemiology studies. This study explores the limitations of current regression models in extrapolation to the low dose region of the dose-response curve due to the existence of unrecognized and uncontrolled confounding, using epidemiological data for lead. Based on the reported data in analyses by Lanphear and colleagues and Crump and colleagues, and drawing on other studies, Wilson and Wilson considered maternal IQ, HOME score, SES, parental education, birthweight, smoking, and race as characteristic variables which may have interaction effects. This analysis identifies confounding variables based on the seven longitudinal cohorts in analyses conducted by Lanphear and colleagues and by Crump and colleagues and confirms maternal IQ, HOME score, maternal education and maternal marital status at birth are "Highly Likely" confounders, while race is a "Likely" confounder. The cohort data were reanalyzed using the methods presented by Crump and colleagues while also considering the interaction among the identified confounding variables. This analysis determined that confounders influence IQ estimates in a quantifiable way that may exceed or at least obscure previously-reported effects of blood lead on IQ with blood lead levels below 5 µg/dL; however, limitations in the datasets make predictions of the low dose dose-response analysis questionable.

A Meta-Analysis of Stressors from the Total Environment Associated with Children's General Cognitive Ability

General cognitive ability, often referred to as ‘general intelligence’, comprises a variety of correlated abilities. Childhood general cognitive ability is a well-studied area of research and can be used to predict social outcomes and perceived success. Early life stage (e.g., prenatal, postnatal, toddler) exposures to stressors (i.e., chemical and non-chemical stressors from the total (built, natural, social) environment) can impact the development of childhood cognitive ability. Building from our systematic scoping review (Ruiz et al., 2016), we conducted a meta-analysis to evaluate more than 100 stressors related to cognitive development. Our meta-analysis identified 23 stressors with a significant increase in their likelihood to influence childhood cognitive ability by 10% or more, and 80 stressors were observed to have a statistically significant effect on cognitive ability. Stressors most impactful to cognition during the prenatal period were related to maternal health and the mother’s ability to access information relevant to a healthy pregnancy (e.g., diet, lifestyle). Stressors most impactful to cognition during the early childhood period were dietary nutrients (infancy), quality of social interaction (toddler), and exposure to toxic substances (throughout early childhood). In conducting this analysis, we examined the relative impact of real-world exposures on cognitive development to attempt to understand the inter-relationships between exposures to both chemical and non-chemical stressors and early developmental life stages. Our findings suggest that the stressors observed to be the most influential to childhood cognitive ability are not permanent and can be broadly categorized as activities/behaviors which can be modified to improve childhood cognition. This meta-analysis supports the idea that there are complex relationships between a child’s total environment and early cognitive development.

Prenatal alcohol exposure and risk of attention deficit hyperactivity disorder in offspring: A retrospective analysis of the millennium cohort study

OBJECTIVE

To investigate the relationship between prenatal maternal alcohol consumption and the risk of attention deficit hyperactivity disorder (ADHD), the strengths and difficulties questionnaire (SDQ) score and abnormal hyperactivity score in seven-year-old children.

METHODS

This study is a retrospective analysis of the Millennium Cohort Study (MCS). Questionnaires were used to gather data on gestational alcohol consumption when children were 9 months old and neurodevelopmental outcomes in offspring at 7 years of age (N = 13,004). Alcohol consumption was classified into never, light, moderate and heavy. Crude and adjusted logistic regression models were used for data analysis.

RESULTS

The total number of women who reported drinking alcohol in pregnancy (the light, moderate and heavy drinking group) was 3916 (30.1%). No significant association was found between light, moderate or heavy gestational alcohol consumption and ADHD (adjusted odds ratio [aOR] for light = 0.80, 95% confidence interval [CI] = [0.53,1.22], aOR for moderate = 0.83, [0.40, 1.74]; aOR for heavy = 1.27, [0.54, 2.98]); for abnormal SDQ score (aOR for light = 0.94, [0.78,1.13], aOR for moderate = 0.70, [0.49,1.00]; aOR for heavy = 1.08, [0.70, 1.66]); for abnormal Hyperactivity score (aOR for light = 1.02, [0.89,1.17]; aOR for moderate = 1.05, [0.82, 1.34]; aOR for heavy = 0.90, [0.62, 1.32]), in offspring.

CONCLUSION

Light, moderate or heavy antenatal alcohol consumption was not associated with an increased susceptibility to ADHD or behavioural outcomes in this study. However, due to the limited number of cases we cannot rule out an increased risk of ADHD in relation to heavy alcohol consumption.

Association of Prenatal Alcohol Exposure and Offspring Depression: A Negative Control Analysis of Maternal and Partner Consumption

BACKGROUND

Previous research has suggested that intrauterine alcohol exposure is associated with a variety of adverse outcomes in offspring. However, few studies have investigated its association with offspring internalizing disorders in late adolescence.

METHODS

Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), we investigated the associations of maternal drinking in pregnancy with offspring depression at age 18 and 24 (n = 13,480). We also examined partner drinking as a negative control for intrauterine exposure for comparison.

RESULTS

Offspring of mothers that consumed any alcohol at 18 weeks gestation were at increased risk of having a diagnosis of depression (fully adjusted model: OR 1.17, 95% CI 1.02 to 1.34), but there was no clear evidence of association between partners' alcohol consumption at 18 weeks gestation during pregnancy and increased risk of offspring depression (fully adjusted model: OR 0.87, 95% CI 0.74 to 1.01). Postestimation tests found a positive difference between the association of maternal and partner alcohol use on offspring depression, showing a stronger association for maternal compared with partner alcohol use (OR 1.41, CI 1.07 to 1.84).

CONCLUSIONS

Maternal drinking in pregnancy was associated with increased risk of offspring depression at age 18. Residual confounding may explain this association, but the negative control comparison of paternal drinking provides some evidence that it may be causal, and this warrants further investigation.

Fetal Alcohol Programming of Subsequent Alcohol Affinity: A Review Based on Preclinical, Clinical and Epidemiological Studies

The anatomo-physiological disruptions inherent to different categories of the Fetal Alcohol Spectrum Disorder do not encompass all the negative consequences derived from intrauterine ethanol (EtOH) exposure. Preclinical, clinical and epidemiological studies show that prenatal EtOH exposure also results in early programming of alcohol affinity. This affinity has been addressed through the examination of how EtOH prenatally exposed organisms recognize and prefer the drug’s chemosensory cues and their predisposition to exhibit heightened voluntary EtOH intake during infancy and adolescence. In altricial species these processes are determined by the interaction of at least three factors during stages equivalent to the 2nd and 3rd human gestational trimester: (i) fetal processing of the drug’s olfactory and gustatory attributes present in the prenatal milieu; (ii) EtOH’s recruitment of central reinforcing effects that also imply progressive sensitization to the drug’s motivational properties; and (iii) an associative learning process involving the prior two factors. This Pavlovian learning phenomenon is dependent upon the recruitment of the opioid system and studies also indicate a significant role of EtOH’s principal metabolite (acetaldehyde, ACD) which is rapidly generated in the brain via the catalase system. The central and rapid accumulation of this metabolite represents a major factor involved in the process of fetal alcohol programming. According to recent investigations, it appears that ACD exerts early positive reinforcing consequences and antianxiety effects (negative reinforcement). Finally, this review also acknowledges human clinical and epidemiological studies indicating that moderate and binge-like drinking episodes during gestation result in neonatal recognition of EtOH’s chemosensory properties coupled with a preference towards these cues. As a whole, the studies under discussion emphasize the notion that even subteratogenic EtOH exposure during fetal life seizes early functional sensory and learning capabilities that pathologically shape subsequent physiological and behavioral reactivity towards the drug.

Early life predictors of intelligence in young adulthood and middle age

BACKGROUND

Studies on early predictors of intelligence often focus on single or few predictors and often on childhood intelligence. This study compared the contributions of a broad selection of potential early predictors of intelligence at different adult ages.

METHODS

Information on predictors was recorded prospectively in the Copenhagen Perinatal Cohort during pregnancy, at delivery, and at 1- and 3-year examinations for children born between 1959-61. Adult intelligence was assessed at three independent follow-ups using three different tests of intelligence: Børge Priens Prøve, Wechsler Adult Intelligence Scale, and Intelligenz-Struktur-Test 2000R. From a total of 4697 cohort members, three non-overlapping samples were derived.

RESULTS

The included predictors explained between 22.2-24.3% of the variance in adult IQ, with parental socioeconomic status and sex explaining 16.2-17.0%. Other consistent predictors were head circumference at birth, increase in head circumference head during the first three years, and 3-year milestones. Head circumference was the most important anthropometric measure compared to measures of weight and length.

CONCLUSION

Besides social status and sex, the strongest and most consistent early predictors of adult intelligence were physical or behavioural characteristics that to some extent reflect brain-and cognitive development.

The causal web of foetal alcohol spectrum disorders: a review and causal diagram

Foetal alcohol spectrum disorders (FASDs) are a leading cause of developmental disability. Prenatal alcohol use is the sole necessary cause of FASD, but it is not always sufficient. Multiple factors influence a child's susceptibility to FASD following prenatal alcohol exposure. Much of the FASD risk factor literature has been limited to discussions of association, rather than causation. While knowledge of predictor variables is important for identifying who is most at risk of FASD and for targeting interventions, causal knowledge is important for identifying effective mechanisms for prevention and intervention programmes. We conducted a systematic search and narrative synthesis of the evidence and used this to create a causal diagram (directed acyclic graph; DAG) to describe the causal pathways to FASD. Our results show that the aetiology of FASD is multifaceted and complex. FASD risk is determined by a range of lifestyle, sociodemographic, maternal, social, gestational, and genetic factors. The causal diagram that we present in this review provides a comprehensive summary of causal risk factors for FASD and can be used as a tool to inform data collection and statistical modelling strategies to minimise bias in future studies of FASD.

Light drinking during pregnancy: Social advantages explain positive correlates with child and early adolescent adjustment

Maternal heavy alcohol use during pregnancy is harmful to offspring's health and adjustment. However, findings from studies on lower levels of prenatal drinking are mixed; a few even predict positive cognitive and psychosocial outcomes. Given that alcohol is a neurotoxin and teratogen, scholars question developmental benefits and point to residual confounding as a potential explanation, particularly as light drinkers are positively selected with respect to health and socioeconomic status. Using prospective, intergenerational data from the nationally-representative Millennium Cohort Study (MCS) in the United Kingdom, we studied associations between mother's drinking during pregnancy and children's cognitive and psychosocial outcomes at ages 3, 5, 7, 11, and 14 years (n = 10,454). We included early life confounders (e.g., maternal education, health, smoking) and mother's cognitive ability, and assessed robustness of relationships across outcomes and alternate drinking classifications. Results of a series of multivariable regression models found no association between light drinking and cognitive and psychosocial outcomes up to and including the age of 14, after controlling for key confounders. Light drinking during pregnancy was linked to higher socioeconomic advantages (e.g., mothers' higher education, professional/managerial occupation, home ownership, cognitive scores), which together accounted for positive associations between light drinking and children's outcomes. Mother's cognitive ability was an especially important confounder.

Antenatal determinants of early childhood talking delay and behavioural difficulties

The determinants of talking delay alone or its comorbidity with behavioural difficulties was examined in 5768 two-year-old members of the Growing Up in New Zealand longitudinal study. Using the MacArthur-Bates Communicative Development inventories and the total difficulties score from the preschool Strengths and Difficulties Questionnaire, a composite measure was created so that children were categorised as showing no language or behavioural concerns (72.5%), behavioural only difficulties (6.1%), language only difficulties (18.1%), and comorbid language and behavioural difficulties (3.3%). Analyses revealed that antenatal factors such as maternal perceived stress, inadequate folate intake, vitamin intake, alcohol consumption during the first trimester and maternal smoking all had a significant effect on child outcomes. In particular, low multivitamin intake and perceived stress during pregnancy were associated with coexisting language and behavioural difficulties. These findings support international research in showing that maternal factors during pregnancy are associated with developmental outcomes in the early childhood period, and demonstrate these associations within a NZ context. Interventions which address maternal stress management and health behaviours during pregnancy could be beneficial to offspring development.

Is breast feeding associated with offspring IQ at age 5? Findings from prospective cohort: Lifestyle During Pregnancy Study

OBJECTIVES

Breast feeding is associated with health benefits for both mother and child, but many studies focusing on neurodevelopment have lacked information on important confounders and few randomised trials exist. Our objective was to examine the influence of breast feeding on child IQ at 5 years of age while taking maternal IQ and other relevant factors into account.

DESIGN

Prospective observational study.

SETTING

Population-based birth cohort in Denmark.

PARTICIPANTS

We used data from The Lifestyle During Pregnancy Study 1782 mother-child pairs sampled from the Danish National Birth Cohort (n=101 042).

OUTCOME MEASURES

Child IQ was assessed at age 5 years by the Wechsler Primary and Preschool Scales of Intelligence-Revised. On the same occasion maternal intelligence was assessed by Wechsler Adult Intelligence Scale and Raven's Standard Progressive Matrices. Exposure data on duration of breast feeding (n=1385) were extracted from telephone interviews conducted when the child was 6 and 18 months, and analyses were weighted by relevant sampling fractions.

RESULTS

In multivariable linear regression analyses adjusted for potential confounders breast feeding was associated with child IQ at 5 years (categorical χ2 test for overall association p=0.03). Compared with children who were breast fed ≤1 month, children breast fed for 2-3, 4-6, 7-9 and 10 or more months had 3.06 (95% CI 0.39 to 5.72), 2.03 (95% CI -0.38 to 4.44), 3.53 (95% CI 1.18 to 5.87) and 3.28 (95% CI 0.88 to 5.67) points higher IQ after adjustment for core confounders, respectively. There was no dose-response relation and further analyses indicated that the main difference in IQ was between breast feeding ≤1 month versus >1 month.

CONCLUSIONS

Breastfeeding duration of 1 month or shorter compared with longer periods was associated with approximately three points lower IQ, but there was no evidence of a dose-response relation in this prospective birth cohort, where we were able to adjust for some of the most critical confounders, including maternal intelligence.

Cognitive function among schoolchildren in Lebanon: association with maternal alcohol drinking and smoking during pregnancy and domestic use of detergents and pesticides during childhood

To evaluate the relation between caregiver exposure to toxics during pregnancy and childhood and the child's cognitive function in Lebanese children. This was a cross-sectional study conducted on Lebanese students in public and private schools from November 2017 to May 2018, enrolling 464 children. A first linear regression, taking the Cattell total score as the dependent variable and taking sociodemographic characteristics and the family history of the child as independent variables, showed that higher age (Beta = 1.65) was significantly associated with higher cognition, whereas a history of eczema in any of the parents (Beta = -7.32) was significantly associated with lower cognition in the child. A second linear regression, taking the Cattell total score as the dependent variable and taking sociodemographic characteristics and the family history of the child, and the exposure to toxics as independent variables, showed that maternal alcohol intake during pregnancy (Beta = -1.07) and detergent mixing (Beta = -1.48) were significantly associated with lower cognition in the child. A third linear regression, taking the Cattell total score as the dependent variable and taking sociodemographic characteristics and the family history of the child, the exposure to toxics and the diseases in the child as independent variables, showed that maternal alcohol intake during pregnancy (Beta = -1.07) and detergent mixing (Beta = -1.45) were significantly associated with lower cognition in the child, whereas a history of eczema in the child before the age of 2 years (Beta = 8.72) was significantly associated with higher cognition in the child. This study is the first to examine the association of a child's prenatal exposure and their exposure during childhood to environmental toxicants with their cognitive function in Lebanon. We consider this study to be important as it shows the possible effect of cleaning products mixing and maternal alcohol consumption on cognitive functions among children in Lebanon.

Prenatal Alcohol Exposure and Suspected Hearing Impairment Among Children: A Population-based Retrospective Cohort Study

Aims

This study aimed to examine the association between prenatal alcohol exposure and hearing impairment among Japanese children using early childhood health check-up data.

Methods

This retrospective cohort study used population-based health check-up data for children who were born between April 2000 and March 2013 in Hofu city, Japan. Logistic regression models were used to evaluate the association between prenatal alcohol exposure and hearing impairment among children at the age of 36 months. The models were adjusted for mother's age, smoking habit, child sex, birth weight, birth order, history of otitis media and familial history of hearing impairment.

Results

Among the 16,211 registered children, 10,680 children had maternal gestational information and underwent a health check-up at the age of 36 months. A total of 10,562 children were included in the analyses, which revealed that 640 children required a re-examination for hearing impairment, 157 children required a detailed examination for hearing impairment and 83 children were receiving treatment for hearing impairment at 36 months. Prenatal alcohol exposure was independently associated with suspected hearing impairment among children after adjusting for potential confounders.

Conclusions

Our findings suggest that prenatal alcohol exposure may adversely affect the auditory system of children.

Short Summary

Prenatal alcohol exposure was associated with suspected hearing impairment among children at 36 months, based on the findings of a population-based retrospective cohort study that used health check-up data from 10,562 Japanese children.

Maternal and partner prenatal alcohol use and infant cognitive development

BACKGROUND

Teratogenicity of heavy prenatal alcohol exposure is established, but uncertainty remains regarding the impact of moderate alcohol exposure on cognitive deficits in infants. Separating in utero effects from environmental confounding is a challenge for observational studies; consideration of alcohol use by partners as well as mothers may help clarify this. This study examined associations between prenatal alcohol use by both mothers and their partners and infant cognitive developmental outcomes at 12-months.

METHODS

Pregnant women (n = 1331) and their partners (n = 699) were recruited from antenatal clinics of three metropolitan public hospitals in Australia, and completed detailed interviews about alcohol consumptions throughout pregnancy. Infants were assessed with the Bayley Scales of Infant Development - Third edition (Bayley) at 12-months of age.

RESULTS

Alcohol use during pregnancy was reported by 65.7% of mothers and 84.1% of partners. Using multiple methods to adjust for confounding factors, no evidence for impaired cognitive ability associated with alcohol use by mothers or their partners was observed. Children born to women who drank low-levels of alcohol had slightly higher Bayley cognitive scores than those born to abstaining women. There was some evidence for an interaction between sociodemographic factors and prenatal alcohol exposure on infant cognitive outcomes.

CONCLUSION

This finding corroborates existing evidence to suggest there are no detrimental effects to infant cognitive development at 12-months of age following low-level prenatal alcohol exposure. Future prospective studies involving families of a broad range of backgrounds would be informative to clarify interaction between alcohol exposure and environmental factors on developmental outcomes.

Low alcohol consumption and pregnancy and childhood outcomes: time to change guidelines indicating apparently 'safe' levels of alcohol during pregnancy? A systematic review and meta-analyses

OBJECTIVES

To determine the effects of low-to-moderate levels of maternal alcohol consumption in pregnancy on pregnancy and longer-term offspring outcomes.

SEARCH STRATEGY

Medline, Embase, Web of Science and Psychinfo from inception to 11 July 2016.

SELECTION CRITERIA

Prospective observational studies, negative control and quasiexperimental studies of pregnant women estimating effects of light drinking in pregnancy (≤32 g/week) versus abstaining. Pregnancy outcomes such as birth weight and features of fetal alcohol syndrome were examined.

DATA COLLECTION AND ANALYSIS

One reviewer extracted data and another checked extracted data. Random effects meta-analyses were performed where applicable, and a narrative summary of findings was carried out otherwise.

MAIN RESULTS

24 cohort and two quasiexperimental studies were included. With the exception of birth size and gestational age, there was insufficient data to meta-analyse or make robust conclusions. Odds of small for gestational age (SGA) and preterm birth were higher for babies whose mothers consumed up to 32 g/week versus none, but estimates for preterm birth were also compatible with no association: summary OR 1.08, 95% CI (1.02 to 1.14), I² 0%, (seven studies, all estimates were adjusted) OR 1.10, 95% CI (0.95 to 1.28), I² 60%, (nine studies, includes one unadjusted estimates), respectively. The earliest time points of exposure were used in the analysis.

CONCLUSION

Evidence of the effects of drinking ≤32 g/week in pregnancy is sparse. As there was some evidence that even light prenatal alcohol consumption is associated with being SGA and preterm delivery, guidance could advise abstention as a precautionary principle but should explain the paucity of evidence.

Data relating to prenatal lead exposure and child IQ at 4 and 8 years old in the Avon Longitudinal Study of Parents and Children

As part of the Avon Longitudinal Study of Parents and Children (ALSPAC), measures of child IQ were collected by trained psychologists. The Wechsler Pre-school and Primary Scale of Intelligence – Revised UK edition (WPPSI) was used at age 4 years in a subsample of children enrolled in ALSPAC (the Children in Focus cohort), chosen at random from the last 6 months of ALSPAC births (about 10% of the participants). At age 8 years all children enrolled in the main cohort were invited to complete a short form of the Wechsler Intelligence Scale for Children (WISC)-III ^UK. Prenatal blood lead (B-Pb) concentrations were measured by inductively-couple plasma mass spectrometry in samples from women at a median gestation age of 11 weeks. Child blood lead was measured by atomic absorption spectrometry in samples from children attending the Children in Focus clinic at age 30 months. Maternal reports at 32 weeks’ gestation were used to generate data on a range of potential confounders. The data were used to determine the associations between prenatal exposure to lead and child IQ at 4 and 8 years. The effect of child B-Pb at 3 years as a moderator of these associations was tested. (For results, please see doi:10.1016/j.neuro.2017.07.003 Taylor et al., (2017)).

Maternal alcohol consumption during pregnancy and child's cognitive performance at 6-8 years of age in rural Burkina Faso: an observational study

Background

In Burkina Faso, it is not uncommon for mothers to drink alcohol, even during pregnancy. We aimed to study the association between maternal alcohol consumption during pregnancy and the child’s cognitive performance using the Kaufman Assessment Battery for Children, 2nd edition (KABC-II) and the Children’s Category Test Level 1 (CCT-1) in rural Burkina Faso.

Methods

We conducted a follow-up study of a community cluster-randomised Exclusive breastfeeding trial, and re-enrolled the children in rural Burkina Faso. A total of 518 children (268 boys and 250 girls) aged 6–8 years were assessed using the KABC-II and the CCT-1. We examined the effect size difference using Cohen’s d and conducted a linear regression analysis to examine the association.

Results

Self-reported alcohol consumption during pregnancy was 18.5% (96/518). Children whose mothers reported alcohol consumption during pregnancy performed significantly poorly for memory and spatial abilities tests from small effect size difference for ‘Atlantis’ (0.27) and ‘Triangle’ (0.29) to moderate effect size difference for ‘Number recall’ (0.72) compared to children whose mothers did not consume alcohol during pregnancy; the exposed children scored significantly higher errors with a small effect size (0.37) at problem solving (CCT-1) test compared to unexposed children.

At unstandardized and standardized multivariable analysis, children whose mothers reported alcohol consumption during pregnancy performed significantly poorer for memory-‘Atlantis’ (p = 0.03) and ‘Number recall’ (p = 0.0001), and spatial ability tests-‘Triangle’ (p = 0.03); they scored significantly higher errors at problem solving CCT-1 test (p = 0.002); all the results were adjusted for age, sex, schooling, stunting, father’s education, mother’s employment and the promotion of exclusive breastfeeding. No statistical association was found for visual abilities-‘Conceptual Thinking’, ‘Face recognition’, ‘Story completion’, and reasoning tests-‘Rover’, ‘Block counting’, and ‘Pattern Reasoning’.

Conclusion

Maternal alcohol consumption during pregnancy is associated with poorer cognitive performance for memory, spatial ability, and problem solving tests in the offspring in rural Burkina Faso. Futures studies needs to assess in more detail the maternal alcohol consumption patterns in Burkina Faso and possible preventive strategies.

From scientific article to press release to media coverage: advocating alcohol abstinence and democratising risk in a story about alcohol and pregnancy

In this article, we follow the approach taken by Riesch and Spiegalhalter in "Careless pork costs lives': Risk stories from science to press release to media' published in this journal, and offer an assessment of one example of a 'risk story'. Using content and thematic qualitative analysis, we consider how the findings of an article 'Fetal Alcohol Exposure and IQ at Age 8: Evidence from a Population-Based Birth-Cohort Study' were framed in the article itself, the associated press release, and the subsequent extensive media coverage. We contextualise this consideration of a risk story by discussing a body of work that critically engages with the development and global proliferation of efforts to advocate for alcohol abstinence to pregnant (and pre-pregnant) women. This work considers the 'democratisation' of risk, a term used to draw attention to the expansion of the definition of the problem of drinking in pregnancy to include any drinking and all women. We show here how this risk story contributed a new dimension to the democratisation of risk through claims that were made about uncertainty and certainty. A central argument we make concerns the contribution of the researchers themselves (not just lobby groups or journalists) to this outcome. We conclude that the democratisation of risk was advanced in this case not simply through journalists exaggerating and misrepresenting research findings, but that communication to the press and the initial interpretation of findings played their part. We suggest that this risk story raises concerns about the accuracy of reporting of research findings, and about the communication of unwarrantedly worrying messages to pregnant women about drinking alcohol.

Contributions of a Child's Built, Natural, and Social Environments to Their General Cognitive Ability: A Systematic Scoping Review

The etiology of a child’s cognitive ability is complex, with research suggesting that it is not attributed to a single determinant or even a defined period of exposure. Rather, cognitive development is the product of cumulative interactions with the environment, both negative and positive, over the life course. The aim of this systematic scoping review was to collate evidence associated with children’s cognitive health, including inherent factors as well as chemical and non-chemical stressors from the built, natural, and social environments. Three databases were used to identify recent epidemiological studies (2003–2013) that examined exposure factors associated with general cognitive ability in children. Over 100 factors were evaluated from 258 eligible studies. We found that recent literature mainly assessed the hypothesized negative effects of either inherent factors or chemical exposures present in the physical environment. Prenatal growth, sleep health, lead and water pollutants showed consistent negative effects. Of the few studies that examined social stressors, results consistently showed cognitive development to be influenced by both positive and negative social interactions at home, in school or the community. Among behavioral factors related to diet and lifestyle choices of the mother, breastfeeding was the most studied, showing consistent positive associations with cognitive ability. There were mostly inconsistent results for both chemical and non-chemical stressors. The majority of studies utilized traditional exposure assessments, evaluating chemical and non-chemical stressors separately. Collective evidence from a limited number of studies revealed that cumulative exposure assessment that incorporates multiple chemical and non-chemical stressors over the life course may unravel the variability in effect on cognitive development and help explain the inconsistencies across studies. Future research examining the interactions of multiple stressors within a child’s total environment, depicting a more real-world exposure, will aid in understanding the cumulative effects associated with a child’s ability to learn.

Maternal lifestyle during pregnancy and child psychomotor development - Polish Mother and Child Cohort study

BACKGROUND

Nowadays special attention is paid to prenatal exposures to maternal lifestyle factors and their impact on a child development.

AIM

The objective of this study was to evaluate the impact of modifiable maternal lifestyle factors on child neurodevelopment based on the Polish Mother and Child Cohort study.

MATERIAL AND METHODS

The current analysis included 538 mother-child pairs. The following factors related to maternal lifestyle were considered: smoking and environmental tobacco smoke (ETS) exposure (based on the cotinine level in maternal saliva measured using LC-ESI+MS/MS method), alcohol consumption and leisure-time physical activity (LTPA) in pregnancy, pre-pregnancy BMI, and folic acid supplementations before and during pregnancy based on questionnaire data. Psychomotor development was assessed in children at the ages of one and two by the Bayley Scales of Infant and Toddler Development.

RESULTS

Significant association was observed between prenatal exposure to tobacco constituents and a decreased child motor development in assessments performed at both ages (β=-0.8, p=0.01; β=-1.4, p<0.001). Maternal pre-pregnancy underweight was associated with decreased language abilities at 12 months of age (β=-5.2, p=0.01) and cognitive and motor development at 24 months of age, for which the associations were of borderline significance (p=0.06). The recommended level of LTPA during pregnancy was beneficial for child language development at two years of age (β=4.8, p=0.02). For alcohol and folic acid consumption there were no significant associations with any of the analyzed domains of child neurodevelopment.

CONCLUSIONS

Children prenatally exposed to tobacco compounds and those of underweight mothers had a decreased psychomotor development. The recommended level of LTPA during pregnancy had positive impact on child development. These results underscore the importance of policies and public health interventions promoting healthy lifestyle among women in reproductive age and during pregnancy.

Alcohol use disorders in pregnancy

Alcohol use disorders (AUDs) are less prevalent in pregnant women than in nonpregnant women, but these disorders can create a host of clinical challenges when encountered. Unfortunately, little evidence is available to guide clinical decision making in this population. Drinking alcohol during pregnancy can have negative consequences on both fetus and mother, but it remains controversial as to the volume of alcohol consumption that correlates with these consequences. Likewise, little evidence is available to support the use of particular pharmacologic interventions for AUDs during pregnancy or to guide the management of alcohol detoxification in pregnant women. The use of benzodiazepines (the mainstay of most alcohol detoxification protocols) in pregnant women is controversial. Nevertheless, despite the lack of robust data to guide management of AUDs in pregnancy, clinicians need to make management decisions when confronted with these challenging situations. In that context, this article reviews the epidemiology of AUDs in pregnancy and the pharmacologic management of both AUDs and alcohol withdrawal in pregnant women, with the goal of informing clinicians about what is known about managing these co-occurring conditions.

The role of NADPH oxidase in a mouse model of fetal alcohol syndrome

OBJECTIVE

Fetal alcohol syndrome (FAS) is the most common cause of nongenetic mental retardation. Oxidative stress is one of the purported mechanisms. Nicotinamide adenine dinucleotide phosphate oxidase (NOX) is an enzyme involved in the production of reactive oxygen species. Our objective was to evaluate NOX in the fetal brain of a well-validated mouse model of FAS.

STUDY DESIGN

Timed, pregnant C57BL/6J mice were injected intraperitoneally with 0.03 mL/g of either 25% ethyl alcohol or saline. Fetal brain, liver, and placenta were harvested on gestational day 18. The unit of analysis was the litter; tissue from 6-8 litters in the alcohol and control group was isolated. Evaluation of messenger ribonucleic acid (mRNA) expression of NOX subunits (DUOX1, DUOX2, NOX1, NOX2, NOX3, NOX4, NOXA1, NOXO1, RAC1, p22phox, and p67phox) was performed using quantitative real-time polymerase chain reaction; alcohol vs placebo groups were compared using a Student t test or a Mann-Whitney test (P < .05).

RESULTS

Alcohol exposed fetal brains showed significant up-regulation in subunits DUOX2 (1.61 ± 0.28 vs 0.84 ± 0.09; P = .03), NOXA1 (1.75 ± 0.27 vs 1.09 ± 0.06; P = .04), and NOXO1 (1.59 ± 0.10 vs 1.28 ± 0.05; P = .02). Differences in mRNA expression in the placenta were not significant; p67phox was significantly up-regulated in alcohol-exposed livers.

CONCLUSION

Various NOX subunits are up-regulated in fetal brains exposed to alcohol. This effect was not observed in the fetal liver or placenta. Given the available evidence, the NOX system may be involved in the causation of FAS through the generation of reactive oxygen species and may be a potential target for preventative treatment in FAS.

Maternal pre-pregnancy BMI and intelligence quotient (IQ) in 5-year-old children: a cohort based study

BACKGROUND

An association between maternal pre-pregnancy BMI and childhood intelligence quotient (IQ) has repeatedly been found but it is unknown if this association is causal or due to confounding caused by genetic or social factors.

METHODS

We used a cohort of 1,783 mothers and their 5-year-old children sampled from the Danish National Birth Cohort. The children participated between 2003 and 2008 in a neuropsychological assessment of cognitive ability including IQ tests taken by both the mother and the child. Linear regression analyses were used to estimate the associations between parental BMI and child IQ adjusted for a comprehensive set of potential confounders. Child IQ was assessed with the Wechsler Primary and Preschool Scales of Intelligence--Revised (WPPSI-R).

RESULTS

The crude association between maternal BMI and child IQ showed that BMI was adversely associated with child IQ with a reduction in IQ of -0.40 point for each one unit increase in BMI. This association was attenuated after adjustment for social factors and maternal IQ to a value of -0.27 (-0.50 to -0.03). After mutual adjustment for the father's BMI and all other factors except maternal IQ, the association between paternal BMI and child IQ yielded a regression coefficient of -0.26 (-0.59 to 0.07), which was comparable to that seen for maternal BMI (-0.20 (-0.44 to 0.04)).

CONCLUSION

Although maternal pre-pregnancy BMI was inversely associated with the IQ of her child, the similar association with paternal BMI suggests that it is not a specific pregnancy related adiposity effect.

Prenatal exposure to binge pattern of alcohol consumption: mental health and learning outcomes at age 11

The objective of the study is to investigate whether episodic binge pattern of alcohol consumption during pregnancy is independently associated with child mental health and academic outcomes. Using data from the prospective, population-based Avon Longitudinal Study of Parents and Children (ALSPAC), we investigated the associations between binge patterns of alcohol consumption during pregnancy (≥4 drinks per day) and child mental health [as rated by both parent (n = 4,610) and teacher (n = 4,274)] and academic outcomes [based on examination results (n = 6,939)] at age 11 years. After adjusting for prenatal and postnatal risk factors, binge pattern of alcohol consumption (≥4 drinks in a day on at least one occasion) during pregnancy was associated with higher levels of mental health problems (especially hyperactivity/inattention) in girls at age 11 years, according to parental report. After disentangling binge-pattern and daily drinking, binge-pattern drinking was independently associated with teacher-rated hyperactivity/inattention and lower academic scores in both genders. Episodic drinking involving ≥4 drinks per day during pregnancy may increase risk for child mental health problems and lower academic attainment even if daily average levels of alcohol consumption are low. Episodic binge pattern of drinking appears to be a risk factor for these outcomes, especially hyperactivity and inattention problems, in the absence of daily drinking.

Predictors of intelligence at the age of 5: family, pregnancy and birth characteristics, postnatal influences, and postnatal growth

Parental education and maternal intelligence are well-known predictors of child IQ. However, the literature regarding other factors that may contribute to individual differences in IQ is inconclusive. The aim of this study was to examine the contribution of a number of variables whose predictive status remain unclarified, in a sample of basically healthy children with a low rate of pre- and postnatal complications. 1,782 5-year-old children sampled from the Danish National Birth Cohort (2003–2007) were assessed with a short form of the Wechsler Preschool and Primary Scale of Intelligence – Revised. Information on parental characteristics, pregnancy and birth factors, postnatal influences, and postnatal growth was collected during pregnancy and at follow-up. A model including study design variables and child’s sex explained 7% of the variance in IQ, while parental education and maternal IQ increased the explained variance to 24%. Other predictors were parity, maternal BMI, birth weight, breastfeeding, and the child’s head circumference and height at follow-up. These variables, however, only increased the explained variance to 29%. The results suggest that parental education and maternal IQ are major predictors of IQ and should be included routinely in studies of cognitive development. Obstetrical and postnatal factors also predict IQ, but their contribution may be of comparatively limited magnitude.

Effect of prenatal alcohol exposure on childhood academic outcomes: contrasting maternal and paternal associations in the ALSPAC study

BACKGROUND

The impact of low-to-moderate levels of alcohol consumption during pregnancy on child cognitive outcomes has been of recent concern. This study has tested the hypothesis that low-to-moderate maternal alcohol use in pregnancy is associated with lower school test scores at age 11 in the offspring via intrauterine mechanisms.

METHODS

We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a birth cohort study based in the South West of England. Analyses were conducted on 7062 participants who had complete data on: maternal and paternal patterns of alcohol use in the first trimester and at 18 weeks' gestation, child's academic outcomes measured at age 11, gender, maternal age, parity, marital status, ethnicity, household crowding, home ownership status and parental education. We contrasted the association of mother's alcohol consumption during pregnancy with child's National Curriculum Key Stage 2 (KS2) test scores with the association for father's alcohol consumption (during the time the mother was pregnant) with child's National Curriculum Key Stage 2 (KS2) test scores. We used multivariate linear regression to estimate mean differences and 95% confidence intervals [CI] in KS2 scores across the exposure categories and computed f statistics to compare maternal and paternal associations.

FINDINGS AND CONCLUSIONS

Drinking up to 1 unit of alcohol a day during pregnancy was not associated with lower test scores. However, frequent prenatal consumption of 4 units (equivalent to 32 grams of alcohol) on each single drinking occasion was associated with reduced educational attainment [Mean change in offspring KS2 score was -0.68 (-1.03, -0.33) for maternal alcohol categories compared to 0.27 (0.07, 0.46) for paternal alcohol categories]. Frequent consumption of 4 units of alcohol during pregnancy may adversely affect childhood academic outcomes via intrauterine mechanisms.

Learning disorder and blood concentration of heavy metals in the United Arab Emirates

Children are frequently exposed to toxic metals in the environment, and their developing central nervous system is particularly vulnerable to their effects. This study examined the blood level of heavy metals in children with learning disorder (LD) as compared to children without LD in the United Arab Emirates (UAE). Significantly high blood concentrations of seven heavy metals were found in children with LD. Further analysis using forward stepwise logistic regression showed that molybdenum levels and family history of developmental problems were the best predictors of LD. Our findings suggest the need for monitoring for toxic metals in the environment.

Prenatal alcohol exposure and offspring cognition and school performance. A 'Mendelian randomization' natural experiment

BACKGROUND

There is substantial debate as to whether moderate alcohol use during pregnancy could have subtle but important effects on offspring, by impairing later cognitive function and thus school performance. The authors aimed to investigate the unconfounded effect of moderately increased prenatal alcohol exposure on cognitive/educational performance.

METHODS

We used mother-offspring pairs participating in the Avon Longitudinal Study of Parents and Children (ALSPAC) and performed both conventional observational analyses and Mendelian randomization using an ADH1B variant (rs1229984) associated with reduced alcohol consumption. Women of White European origin with genotype and self-reported prenatal alcohol consumption, whose offspring's IQ score had been assessed in clinic (N=4061 pairs) or Key Stage 2 (KS2) academic achievement score was available through linkage to the National Pupil Database (N=6268), contributed to the analyses.

RESULTS

Women reporting moderate drinking before and during early pregnancy were relatively affluent compared with women reporting lighter drinking, and their children had higher KS2 and IQ scores. In contrast, children whose mothers' genotype predisposes to lower consumption or abstinence during early pregnancy had higher KS2 scores (mean difference +1.7, 95% confidence interval +0.4, +3.0) than children of mothers whose genotype predisposed to heavier drinking, after adjustment for population stratification.

CONCLUSIONS

Better offspring cognitive/educational outcomes observed in association with prenatal alcohol exposure presumably reflected residual confounding by factors associated with social position and maternal education. The unconfounded Mendelian randomization estimates suggest a small but potentially important detrimental effect of small increases in prenatal alcohol exposure, at least on educational outcomes.

Light drinking versus abstinence in pregnancy - behavioural and cognitive outcomes in 7-year-old children: a longitudinal cohort study

OBJECTIVE

To assess whether light drinking in pregnancy is linked to unfavourable developmental outcomes in children.

DESIGN

Prospective population-based cohort.

SETTING

UK.

POPULATION

Ten thousand five hundred and thirty-four 7-year-olds.

METHODS

Quasi-experimental using propensity score matching (PSM) to compare children born to light (up to 2 units per week) and non-drinkers.

MAIN OUTCOME MEASURES

Behavioural difficulties rated by parents and teachers; cognitive test scores for reading, maths and spatial skills.

RESULTS

Ordinary least squares (OLS) regression and PSM analyses are presented. For behavioural difficulties, unadjusted estimates for percentage standard deviation (SD) score differences ranged from 2 to 14%. On adjustment for potential confounders, differences were attenuated, with a loss of statistical significance, except for teacher-rated boys' difficulties. For boys, parent-rated behavioural difficulties: unadjusted, -11.5; OLS, -4.3; PSM, -6.8; teacher-rated behavioural difficulties: unadjusted, -13.9; OLS, -9.6; PSM, -10.8. For girls, parent-rated behavioural difficulties: unadjusted, -9.6; OLS, -2.9; PSM, -4.5; teacher-rated behavioural difficulties: unadjusted, -2.4; OLS, 4.9; PSM, 3.9. For cognitive test scores, unadjusted estimates for differences ranged between 12 and 21% of an SD score for reading, maths and spatial skills. After adjustment for potential confounders, estimates were reduced, but remained statistically significantly different for reading and for spatial skills in boys. For boys, reading: unadjusted, 20.9; OLS, 8.3; PSM, 7.3; maths: unadjusted, 14.7; OLS, 5.0; PSM, 6.5; spatial skills: unadjusted, 16.2; OLS, 7.6; PSM, 8.1. For girls, reading: unadjusted, 11.6; OLS, -0.3; PSM, -0.5; maths: unadjusted, 12.9; OLS, 4.3; PSM, 3.9; spatial skills: unadjusted, 16.2; OLS, 7.7; PSM, 6.4.

CONCLUSION

The findings suggest that light drinking during pregnancy is not linked to developmental problems in mid-childhood. These findings support current UK Department of Health guidelines on drinking during pregnancy.

The association of mild, moderate, and binge prenatal alcohol exposure and child neuropsychological outcomes: a meta-analysis

BACKGROUND

The objective of this review is to evaluate the literature on the association between mild, moderate, and binge prenatal alcohol exposure and child neurodevelopment.

METHODS

Meta-analysis with systematic searches of MEDLINE (1970 through August 2012), EMBASE (1988 through August 2012), and PsycINFO(®) (1970 through August 2012) and examination of selected references.

RESULTS

From 1,593 articles, we identified 34 presenting data from cohort studies that met our inclusion criteria. Information on study population, outcomes, measurement instruments, timing and quantification of alcohol exposure, covariates, and results was abstracted. Outcomes included academic performance, attention, behavior, cognition, language skills, memory, and visual and motor development. The quality of each article was assessed by 2 researchers using the Newcastle-Ottawa Scale. Based on 8 studies of 10,000 children aged 6 months through 14 years, we observed a significant detrimental association between any binge prenatal alcohol exposure and child cognition (Cohen's d [a standardized mean difference score] -0.13; 95% confidence interval [CI], -0.21, -0.05). Based on 3 high-quality studies of 11,900 children aged 9 months to 5 years, we observed a statistically significant detrimental association between moderate prenatal alcohol exposure and child behavior (Cohen's d -0.15; 95% CI, -0.28, -0.03). We observed a significant, albeit small, positive association between mild-to-moderate prenatal alcohol exposure and child cognition (Cohen's d 0.04; 95% CI, 0.00, 0.08), but the association was not significant after post hoc exclusion of 1 large study that assessed mild consumption nor was it significant when including only studies that assessed moderate alcohol consumption. None of the other completed meta-analyses resulted in statistically significant associations between mild, moderate, or binge prenatal alcohol exposure and child neuropsychological outcomes.

CONCLUSIONS

Our findings support previous findings suggesting the detrimental effects of prenatal binge drinking on child cognition. Prenatal alcohol exposure at levels less than daily drinking might be detrimentally associated with child behavior. The results of this review highlight the importance of abstaining from binge drinking during pregnancy and provide evidence that there is no known safe amount of alcohol to consume while pregnant.

Prenatal alcohol exposure and childhood balance ability: findings from a UK birth cohort study

OBJECTIVE

To investigate the association of prenatal alcohol exposure with balance in10-year-old children.

DESIGN

Population-based prospective longitudinal study.

SETTING

Former Avon region of UK (Southwest England).

PARTICIPANTS

6915 children from the Avon Longitudinal Study of Parents and Children who had a balance assessment at age 10 and had data on maternal alcohol consumption.

OUTCOME MEASURES

3 composite balance scores: dynamic balance (beam-walking), static balance eyes open, static balance eyes closed (heel-to-toe balance on a beam and standing on one leg, eyes open or closed).

RESULTS

Most mothers (95.5%) consumed no-to-moderate amounts (3-7 glasses/week) of alcohol during pregnancy. Higher total-alcohol consumption was associated with maternal-social advantage, whereas binge drinking (≥4 units/day) and abstinence were associated with maternal social disadvantage. No evidence was found of an adverse effect of maternal-alcohol consumption on childhood balance. Higher maternal-alcohol use during pregnancy was generally associated with better offspring outcomes, with some specific effects appearing strong (static balance eyes open and moderate total alcohol exposure at 18 weeks, adjusted OR 1.23 (95% CI 1.01 to 1.49); static balance eyes closed and moderate total alcohol exposure at 18 weeks, adjusted OR 1.25 (95% CI 1.06 to 1.48). Similar results were found for both paternal and postnatal maternal alcohol exposure. A Mendelian-randomization approach was used to estimate the association between maternal genotype and offspring balance using the non-synonymous variant rs1229984*A (ADH1B) to proxy for lower maternal alcohol consumption; no strong associations were found between this genotype/proxy and offspring balance.

CONCLUSIONS

No evidence was found to indicate that moderate maternal alcohol consumption in this population sample had an adverse effect on offspring balance at age 10. An apparent beneficial effect of higher total maternal alcohol consumption on offspring balance appeared likely to reflect residual confounding.

Alcohol use in pregnancy: prevalence and predictors in the Longitudinal Study of Australian Children

INTRODUCTION AND AIMS

This study aimed to estimate the prevalence and describe the patterns of alcohol use during pregnancy among Australian mothers. The study also aimed to examine the characteristics associated with alcohol use in pregnancy.

DESIGN AND METHODS

Data comprised two representative samples of families (infant cohort = 5107 parents of 0- to 1-year-olds; child cohort = 4983 parents of 4- to 5-year-olds) from the 2005 Longitudinal Study of Australian Children.

RESULTS

Alcohol use in pregnancy was reported by 37.6% of mothers of infants aged 0-1 years and 27.6% of mothers of children aged 4-5 years. The majority of women reported low level/occasional use of alcohol but, when extrapolated to population level, this equates to 131,250 children in these two age groups exposed to alcohol in utero, with over 1000 children exposed to alcohol most days and an estimated 671 infants exposed to three or more drinks per occasion. Among mothers of infants, alcohol use in pregnancy was associated with increasing maternal age, higher education, greater economic advantage and fewer physical health problems in pregnancy. Among mothers of children, maternal drinking in pregnancy was associated with increasing maternal age and smoking in pregnancy.

DISCUSSION AND CONCLUSIONS

Alcohol use during pregnancy is common with around one-third of all mothers reporting use. Most women reported only occasional use, and among those who were asked, consumed one standard drink on average per occasion. Significant numbers were exposed to three or more drinks on one occasion or to alcohol most days while in utero. National guidelines recommend abstinence as no 'safe' threshold has been determined. Public health campaigns are needed to educate pregnant women regarding national guidelines.

Cohort Profile: the Avon Longitudinal Study of Parents and Children: ALSPAC mothers cohort

Summary The Avon Longitudinal Study of Children and Parents (ALSPAC) was established to understand how genetic and environmental characteristics influence health and development in parents and children. All pregnant women resident in a defined area in the South West of England, with an expected date of delivery between 1st April 1991 and 31st December 1992, were eligible and 13761 women (contributing 13867 pregnancies) were recruited. These women have been followed over the last 19-22 years and have completed up to 20 questionnaires, have had detailed data abstracted from their medical records and have information on any cancer diagnoses and deaths through record linkage. A follow-up assessment was completed 17-18 years postnatal at which anthropometry, blood pressure, fat, lean and bone mass and carotid intima media thickness were assessed, and a fasting blood sample taken. The second follow-up clinic, which additionally measures cognitive function, physical capability, physical activity (with accelerometer) and wrist bone architecture, is underway and two further assessments with similar measurements will take place over the next 5 years. There is a detailed biobank that includes DNA, with genome-wide data available on >10000, stored serum and plasma taken repeatedly since pregnancy and other samples; a wide range of data on completed biospecimen assays are available. Details of how to access these data are provided in this cohort profile.

Effects of tobacco smoking in pregnancy on offspring intelligence at the age of 5

The aim of the study was to examine the effects of tobacco smoking in pregnancy on children's IQ at the age of 5. A prospective follow-up study was conducted on 1,782 women, and their offspring were sampled from the Danish National Birth Cohort. At 5 years of age, the children were tested with the Wechsler Preschool and Primary Scale of Intelligence-Revised. Parental education, maternal IQ, maternal alcohol consumption in pregnancy, the sex and age of the child, and tester were considered core confounders, but the full model also controlled for prenatal paternal smoking, maternal age and Bodymass Mass Index, parity, family/home environment, postnatal parental smoking, breast feeding, the child's health status, and indicators for hearing and vision impairments. Unadjusted analyses showed a statistically significant decrement of 4 points on full-scale IQ (FSIQ) associated with smoking 10+ cigarettes per day compared to nonsmoking. After adjustment for potential confounders, no significant effects of prenatal exposure to tobacco smoking were found. Considering the indisputable teratogenic effects of tobacco smoking, these findings should be interpreted with caution. Still, the results may indicate that previous studies that failed to control for important confounders, particularly maternal intelligence, may be subject to substantial residual confounding.

Fetal alcohol exposure and IQ at age 8: evidence from a population-based birth-cohort study

Background

Observational studies have generated conflicting evidence on the effects of moderate maternal alcohol consumption during pregnancy on offspring cognition mainly reflecting problems of confounding. Among mothers who drink during pregnancy fetal alcohol exposure is influenced not only by mother’s intake but also by genetic variants carried by both the mother and the fetus. Associations between children’s cognitive function and both maternal and child genotype at these loci can shed light on the effects of maternal alcohol consumption on offspring cognitive development.

Methods

We used a large population based study of women recruited during pregnancy to determine whether genetic variants in alcohol metabolising genes in this cohort of women and their children were related to the child’s cognitive score (measured by the Weschler Intelligence Scale) at age 8.

Findings

We found that four genetic variants in alcohol metabolising genes in 4167 children were strongly related to lower IQ at age 8, as was a risk allele score based on these 4 variants. This effect was only seen amongst the offspring of mothers who were moderate drinkers (1–6 units alcohol per week during pregnancy (per allele effect estimates were −1.80 (95% CI = −2.63 to −0.97) p = 0.00002, with no effect among children whose mothers abstained during pregnancy (0.16 (95%CI = −1.05 to 1.36) p = 0.80), p-value for interaction  = 0.009). A further genetic variant associated with alcohol metabolism in mothers was associated with their child’s IQ, but again only among mothers who drank during pregnancy.

The effects of low to moderate prenatal alcohol exposure in early pregnancy on IQ in 5-year-old children

OBJECTIVE

To examine the effects of low to moderate maternal alcohol consumption during early pregnancy on children's intelligence (IQ) at age 5 years.

DESIGN

Prospective follow-up study.

SETTING

Neuropsychological testing in four Danish cities 2003-2008.

POPULATION

A cohort of 1628 women and their children sampled from the Danish National Birth Cohort.

METHODS

Participants were sampled based on maternal alcohol consumption during pregnancy. At 5 years of age, children were tested with the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R). Parental education, maternal IQ, maternal smoking in pregnancy, the child's age at testing, gender, and tester were considered core confounding factors, whereas the full model also controlled for maternal binge drinking, age, BMI, parity, home environment, postnatal smoking in the home, health status, and indicators for hearing and vision impairments.

MAIN OUTCOME MEASURES

The WPPSI-R.

RESULTS

No differences in test performance were observed between children whose mothers reported consuming between one and four or between five and eight drinks per week at some point during pregnancy, compared with children of mothers who abstained. For women who reported consuming nine or more drinks per week no differences were observed for mean differences; however, the risks of low full-scale IQ (OR 4.6; 95% CI 1.2-18.2) and low verbal IQ (OR 5.9; 95% CI 1.4-24.9) scores, but not low performance IQ score, were increased.

CONCLUSIONS

Maternal consumption of low to moderate quantities of alcohol during pregnancy was not associated with the mean IQ score of preschool children. Despite these findings, acceptable levels of alcohol use during pregnancy have not yet been established, and conservative advice for women continues to be to avoid alcohol use during pregnancy.

The effect of alcohol binge drinking in early pregnancy on general intelligence in children

OBJECTIVE

To examine the effects of binge alcohol consumption during early pregnancy, including the number of binge episodes and the timing of binge drinking, on general intelligence in 5-year-old children.

DESIGN

Follow-up study.

SETTING

Neuropsychological testing in four Danish cities 2003-2008.

POPULATION

A cohort of 1617 women and their children sampled from the Danish National Birth Cohort.

METHODS

Participants were sampled on the basis of maternal alcohol consumption during pregnancy. At 5 years of age the children were tested with six subtests from the Wechsler Preschool and Primary Scale of Intelligence - Revised (WPPSI-R). Parental education, maternal IQ, prenatal maternal smoking, the child's age at testing, the gender of the child, and tester were considered core confounding factors, whereas the full model also controlled for prenatal maternal average alcohol intake, maternal age, maternal pre-pregnancy body mass index (BMI), parity, home environment, postnatal parental smoking, health status, and indicators for hearing and vision impairment.

MAIN OUTCOME MEASURE

WPPSI-R.

RESULTS

There were no systematic or significant differences in general intelligence between children of mothers reporting binge drinking and children of mothers with no binge episodes, except that binge drinking in gestational weeks 1-2 significantly reduced the risk of low, full-scale IQ (OR 0.54; 95% CI 0.31-0.96) when adjusted for core confounding factors. The results were otherwise not statistically significantly related to the number of binge episodes (with a maximum of 12) and timing of binge drinking.

CONCLUSIONS

We found no systematic association between binge drinking during early pregnancy and child intelligence. However, binge drinking reduced the risk of low, full-scale IQ in gestational weeks 1-2. This finding may be explained by residual confounding.

The effect of different alcohol drinking patterns in early to mid pregnancy on the child's intelligence, attention, and executive function

OBJECTIVE

To conduct a combined analysis of the estimated effects of maternal average weekly alcohol consumption, and any binge drinking, in early to mid pregnancy on general intelligence, attention, and executive function in 5-year-old children.

DESIGN

Follow-up study.

SETTING

Neuropsychological testing in four Danish cities 2003-2008.

POPULATION

A cohort of 1628 women and their children sampled from the Danish National Birth Cohort.

METHODS

Participants were sampled based on maternal alcohol consumption during early pregnancy. At age 5 years, the children were tested for general intelligence, attention, and executive function. The three outcomes were analysed together in a multivariate model to obtain joint estimates and P values for the association of alcohol across outcomes. The effects of low to moderate alcohol consumption and binge drinking in early pregnancy were adjusted for a wide range of potential confounding factors.

MAIN OUTCOME MEASURES

Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R), the Test of Everyday Attention for Children at Five (TEACh-5), and the Behavior Rating Inventory of Executive Functions (BRIEF) scores.

RESULTS

Multivariate analyses showed no statistically significant effects arising from average weekly alcohol consumption or any binge drinking, either individually or in combination. These results replicate findings from separate analyses of each outcome variable.

CONCLUSIONS

The present study contributes comprehensive methodological and statistical approaches that should be incorporated in future studies of low to moderate alcohol consumption and binge drinking during pregnancy. Furthermore, as no safe level of drinking during pregnancy has been established, the most conservative advice for women is not to drink alcohol during pregnancy. However, the present study suggests that small volumes consumed occasionally may not present serious concern.

The effects of low to moderate alcohol consumption and binge drinking in early pregnancy on executive function in 5-year-old children

OBJECTIVE

To examine the effects of low to moderate maternal alcohol consumption and binge drinking in early pregnancy on children's executive functions at the age of 5 years.

DESIGN

Follow-up study.

SETTING

Neuropsychological testing in four Danish cities 2003-2008. Population A cohort of 1628 women and their children sampled from the Danish National Birth Cohort.

METHODS

Participants were sampled based on maternal alcohol drinking patterns during early pregnancy. When the children were 5 years old, the parent and teacher forms of the Behaviour Rating Inventory of Executive Function (BRIEF) were completed by the mothers and a preschool teacher. Parental education, maternal IQ, prenatal maternal smoking, the child's age at testing, and the child's gender were considered core confounding factors. The full model also included maternal binge drinking or low to moderate alcohol consumption, maternal age, parity, maternal marital status, family home environment, postnatal parental smoking, pre-pregnancy maternal body mass index (BMI), and the health status of the child.

MAIN OUTCOME MEASURES

The BRIEF parent and teacher forms.

RESULTS

Adjusted for all potential confounding factors, no statistically significant associations between maternal low to moderate average weekly consumption and BRIEF index scores were observed.In adjusted analyses, binge drinking in gestational week 9 or later was significantly associated with elevated Behavioural Regulation Index parent Scores (2.04, 95% CI 0.33–3.76), and with the risk of high scores on the Metacognitive Index assessed by the teacher (OR 2.06, 95% CI 1.01–4.23) [corrected].

CONCLUSIONS

This study did not observe significant effects of low to moderate alcohol consumption during pregnancy on executive functioning at the age of 5 years. Furthermore, only weak and no consistent associations between maternal binge drinking and executive functions were observed.