Is there a fetal effect with low to moderate alcohol use before or during pregnancy?

Prevalence and Patterns of Prenatal Alcohol Exposure in Australian Cohort and Cross-Sectional Studies: A Systematic Review of Data Collection Approaches

This study sought to determine data collection approaches in Australian cohort studies and explore the potential impact on reported prenatal alcohol exposure (PAE) prevalence and patterns. Inclusion criteria were that studies related to a general Australian antenatal population where PAE was assessed and reported. Studies were excluded if they were not peer reviewed, examined the prevalence of PAE in pregnancies complicated by alcohol-use disorders, or were published in a language other than English. A systematic search of five electronic databases (PubMed, Embase, CINAHL, Web of Science, and Scopus) was conducted. Risk of bias was assessed using the Effective Public Health Practice Project quality assessment tool. Results were synthesised using MetaXL. Data from 16 separate birth cohorts (n = 78 articles) were included. Included cohorts were either general cohorts that included alcohol as a variable or alcohol-focused cohorts that were designed with a primary focus on PAE. PAE prevalence was estimated as 48% (95% CI: 38 to 57%). When subgroup analysis was performed, estimates of PAE prevalence when self-administered surveys and interviews were used for data collection were 53% (95% CI: 41% to 64%) and 43% (95% CI: 28% to 59%), respectively. Use of trained assessors was an influencing factor of the prevalence estimates when data were collected via interview. Alcohol-focused studies reported higher prevalence of PAE, regardless of method of survey administration. Where interviewer training is not possible, self-administered questionnaires will likely provide the most reliable PAE estimates. No funding sources are relevant to mention. Review was registered with PROSPERO (CRD42020204853).

The impact of high apparent temperature on spontaneous preterm delivery: a case-crossover study

BACKGROUND

Despite the prediction that temperatures are expected to increase in the future, little is known about the health effects of increasing temperatures on pregnant women. The objective of this study was to investigate the impact of apparent temperature on spontaneous preterm delivery (PTD).

METHODS

A case-crossover study of 14,466 singleton spontaneous preterm deliveries occurring between January 1, 1995 and December 31, 2009 among Kaiser Permanente Northern California (KPNC) members was conducted. Preterm deliveries were identified through KPNC's Electronic Health Records (EHR) data. Data on gestational age at delivery, infant sex, and maternal address were also extracted from KPNC's EHR and linked to meteorologic and air pollution monitoring data based on residential zip code.

RESULTS

An 11.6% (95% CI: 4.1, 19.7) increase in spontaneous PTD was associated with a 10 °F (5.6 °C) increase in weekly average (lag06) apparent temperature, during the warm season. During the cold season, increases in apparent temperature did not significantly impact the overall effect of spontaneous PTD (6.2%, (95% CI: -3.0, 16.2) per 10 °F (5.6 °C) increase in weekly average (lag06) apparent temperature). Significant differences in the relationship between apparent temperature and spontaneous PTD emerged for region, gestational age and infant sex, during the cold season. No significant differences emerged for air pollutants.

CONCLUSIONS

Our findings provide evidence for an increase in the odds of spontaneous PTD associated with increases in apparent temperature, especially during the warm season.

Low-to-moderate prenatal alcohol consumption and the risk of selected birth outcomes: a prospective cohort study

PURPOSE

To estimate whether low-to-moderate prenatal alcohol exposure is associated with selected birth outcomes.

METHODS

Low-to-moderate prenatal alcohol drinking and effects on low birthweight, preterm delivery, intrauterine growth restriction, and selected neonatal outcomes were evaluated among 4496 women and singleton infants. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multivariable logistic regression, controlling for confounding variables.

RESULTS

Early pregnancy drinking was associated with reduced odds of low birthweight, OR, 0.66 (95% CI, 0.46-0.96) and birth length less than 10th percentile, OR, 0.74 (95% CI, 0.56-0.97). Drinking during the first 3 months showed lower odds for birth length and head circumference less than 10th percentile, OR, 0.56 (95% CI, 0.36-0.87) and OR, 0.69 (95% CI, 0.50-0.96), respectively. Third trimester drinking was associated with lower odds for low birthweight, OR, 0.56 (95% CI, 0.34-0.94) and preterm delivery, OR, 0.60 (95% CI, 0.42-0.87).

CONCLUSIONS

Our results suggest low-to-moderate alcohol exposure during early and late gestation is not associated with increased risk of low birthweight, preterm delivery, intrauterine growth restriction, and most selected perinatal outcomes.

Mothers with alcoholic liver disease and the risk for preterm and small-for-gestational-age birth

AIMS

To study pregnancy outcome in women with alcoholic liver disease (ALD).

METHODS

Using the Swedish nation-wide Patient and Medical Birth Registers, we investigated risk of adverse pregnancy outcome in 720 women diagnosed with ALD before and 1720 diagnosed after birth and compared them with 24 460 population-based control births.

RESULTS

Women with ALD diagnosed before or after birth were generally of higher age and body mass index, more likely to smoke cigarettes during pregnancy and to have a low socio-economic status compared with controls. Women diagnosed with ALD before birth had an increased risk of moderately and very preterm birth, adjusted odd ratio (OR) = 1.53 (95% confidence interval (CI): 1.37-1.72 and 1.15-2.06 95%), respectively. Infants of mothers with ALD before birth were more often small-for-gestational age, adjusted OR = 1.22 (95% CI: 1.05-1.43), and were at increased risk for low Apgar scores (<7) at 5 min, adjusted OR = 1.49 (95% CI: 1.15-1.92) compared with controls. Similar associations with slightly lower-risk estimates were found among women diagnosed with ALD after birth.

CONCLUSIONS

ALD is associated with adverse-birth outcomes, highlighting the importance of screening women for alcohol dependence in antenatal care.

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.

Head circumference at birth and exposure to tobacco, alcohol and illegal drugs during early pregnancy

AIMS

We aimed to assess the effects of exposure to tobacco smoke, alcohol and illegal drugs during early pregnancy on the head circumference (HC) at birth of otherwise healthy neonates.

METHODS

A follow-up study from the first trimester of pregnancy to birth was carried out in 419 neonates. An environmental reproductive health form was used to record data of substance exposure obtained during the first obstetric visit at the end of the first trimester. A multiple linear regression model was created for this purpose.

RESULTS

Alcohol intake during pregnancy and medical ionizing radiation exposure were the most significant predictors of HC. The mothers' alcohol consumption increased with the mothers' and fathers' education level, net family income and fathers' alcohol consumption. In contrast, maternal smoking decreased with increasing mothers' and fathers' education level and net family income. About 13% of the surveyed embryos were exposed to illegal drugs.

CONCLUSIONS

Mild to moderate alcohol consumption diminishes the at-birth HC of theoretically healthy newborns in a linear form. There was no threshold dose. We perceived a need for increasing the awareness, and for training, of health care professionals and parents, in regard to risks of alcohol consumption and for recommending abstinence of these substances in both parents during pregnancy. It should also be remembered that medical ionizing radiation should be performed only during the first half of the cycle in fertile women. We think that our study has an important social impact as it affords data for implementing policies for promoting "healthy pregnancies".

Teratogenic exposures

A consideration of teratogenic exposures includes not only an agent (chemical, radiation, biologic) but an exposure level and timing of exposure. There are criteria by which exposures are evaluated for a causal connection with an abnormal outcome. We here review some teratogenic exposures and discuss how they were initially described and confirmed. We have limited our discussion to some of the exposures for which a connection to structural malformations has been accepted in some quarters, and we indicate some exposures for which a causal association awaits confirmation. We recommend that counselors find a reliable and updatable source of information on exposures during pregnancy.

Smoking in pregnancy

During nine months of pregnancy, a woman who smokes 20 cigarettes each day will inhale nicotine, tar and carbon monoxide more than 50 000 times. This smoke contains chemicals known to be mutagenic and carcinogenic and will interfere with the normal growth and development of her child. Recent studies have revealed disturbing long-term consequences for the offspring. This article reviews the constituents of cigarette smoke, the effects of tobacco usage on the pregnancy, child and placenta, and strategies by which smoking during pregnancies may be prevented.

Pregnancy alcohol consumption

Alcohol was discovered soon after the development of waterproof pots to store and transport water and fruit. Liquids produced by spontaneous fermentation of grains, sugars and fruits were found to enhance pleasure. During the middle ages alchemists discovered that distillation increased this power and thought they had found the elixir of life. Since then almost every culture has used alcohol. Each society has introduced its own restrictions on the availability, exports, imports and consumption of alcoholic beverages within its religious and political structure. Generally, drinking levels which interfere with self-control or result in individual, familial or societal harm are disapproved by all cultures.

Prenatal alcohol exposure and attention, learning and intellectual ability at 14 years: a prospective longitudinal study

BACKGROUND

A range of adverse birth outcomes is associated with heavy prenatal alcohol exposure.

AIM

To examine the effects of moderate levels of alcohol consumption during pregnancy on children's intellectual ability, learning and attention at 14 years of age.

STUDY DESIGN AND SUBJECTS

The Mater-University of Queensland Study of Pregnancy involves a prospective birth cohort of 7223 singletons whose mothers were enrolled at the first antenatal visit. At 14 years, 5139 mothers and adolescents completed attentional and learning questionnaires, and 3731 adolescents completed psychometric assessments.

OUTCOME MEASURES

For adolescents, the Wide Range Achievement Test--Revised (WRAT-R) and Raven's Standard Progressive Matrices Test (Raven's) were administered. Mothers completed the Child Behaviour Checklist (CBCL) and adolescents completed the Youth Self Report (YSR). Learning was assessed by a series of questions in the mother and adolescent questionnaires. Maternal measures included the quantity and frequency of alcohol consumption, and the extent of binge drinking.

RESULTS

For consumption of <1 glass/day in early or late pregnancy, there was no association with any attention, learning or cognitive outcomes. The strongest estimates of effect were found among those consuming > or =1 glasses/day. Exposure in late pregnancy was associated with increased prevalence of overall learning difficulty in the unadjusted, although not the adjusted analysis. Binge drinking was associated with a higher prevalence of Raven's score <85 (1 standard deviation).

CONCLUSIONS

Although a number of study limitations need to be considered, the results suggest that consumption at the level of <1 drink/day does not lead to adverse outcomes in relation to attention, learning and cognitive abilities, as measured in the current research.

Alcohol Consumption During Pregnancy in Nonindigenous West Australian Women

BACKGROUND

High alcohol intake in pregnancy has been linked to abnormal fetal development. There are limited published data in Australia on standard drinks of alcohol consumed on a typical occasion during the periconceptional period or pregnancy.

METHODS

During 1995 to 1997, a 10% random sample of all nonindigenous women giving birth in Western Australia was surveyed 12 weeks after delivery (N=4,839). Women were asked questions about alcohol consumption in each of the 4 time periods: the 3 months before pregnancy and each trimester of pregnancy. Questions were framed to measure volume, frequency, and type of alcoholic beverage.

RESULTS

46.7% of the women had not planned their pregnancy. Most women (79.8%) reported drinking alcohol in the 3 months before pregnancy, with 58.7% drinking alcohol in at least 1 trimester of pregnancy. The proportion of women consuming 1 to 2 drinks on a typical occasion did not change much during pregnancy, but the number of occasions declined. Although the proportion of women consuming more than 2 standard drinks on a typical occasion declined after the first trimester, 19.0% of women consumed this amount in at least 1 trimester of pregnancy and 4.3% of women consumed 5 or more standard drinks on a typical occasion in at least 1 trimester of pregnancy. In the first trimester of pregnancy, 14.8% of women drank outside the current Australian guideline for alcohol consumption in pregnancy, decreasing to 10% in the second and third trimesters.

CONCLUSIONS

Women generally reduced their average alcohol consumption and the number of standard drinks on a typical occasion as their pregnancy progressed, although 10 to 14% were drinking outside current guidelines for pregnancy. It is important that all women of child-bearing age are aware, well before they consider pregnancy, of the risks of drinking alcohol during pregnancy so they can make informed decisions about their alcohol consumption in pregnancy.

The effect of health compromising behaviors on preterm births

OBJECTIVES

The objective of our study was to determine whether there were combined effects of smoking, alcohol, and illicit drug use during pregnancy on the frequency of preterm births, and if so, the magnitude of the association after adjusting for confounding factors.

METHODS

We conducted a retrospective cohort study of singleton live births in Kansas City, Missouri from 1990-2002. We defined health compromising behaviors as the use of cigarettes, alcohol, and illicit drugs. The effect of these behaviors on preterm births was considered for each substance individually, and in combination. The rates of preterm births for these groups were calculated. Using logistic regression, adjusted odds ratios were used to estimate the relative risk of preterm births among these groups.

RESULTS

Over 13% of infants born to women who smoked were preterm, compared to 9.6% for non-smokers. Of infants born to women who reported alcohol use, 17.3% were preterm compared to 10.1% for non-drinkers. Smoking and alcohol use in combination was associated with 18.0% preterm births, while alcohol and drug use in combination was associated with 20.8% preterm births. The use of all three substances was associated with 31.4% preterm births.

CONCLUSION

Women who engaged in health compromising behaviors during pregnancy showed an increased proportion of preterm births compared to those who did not. There is significant interaction between these behaviors leading to higher rates of preterm births than predicted by their additive effects. To decrease preterm births, we must deal with the effects of smoking, drinking, and drug use simultaneously.

Pattern of alcohol consumption during pregnancy and risk for low birth weight

PURPOSE

The effects of moderate alcohol drinking on low birth weight are not clear, and conflicting results have been reported. We assessed the influence of different patterns of alcohol drinking during pregnancy on low birth weight.

METHODS

A case-control study was carried out at the University of Cantabria Hospital, Spain, from 1998 to 2002. Cases (n = 552) were mothers delivering a single newborn weighing less than 2500 g. Controls (n = 1451) were selected from a random sample of all delivering women. Information was obtained from personal interview, clinical charts, and prenatal care records. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated. Adjustment for potential confounders was made by means of logistic regression.

RESULTS

Alcohol consumption of less than 6 g/day decreased the risk for low birth weight (adjusted OR = 0.64; 95% CI, 0.46-0.88). A similar result was obtained for moderate drinkers (<12 g/day) on weekends only. The opposite relationship was observed between alcohol consumption on weekdays of 12 g/day or greater (adjusted OR = 2.67; 95% CI, 1.39-5.12), not observed in those drinking on weekends only. The interaction between alcohol consumption and tobacco smoking was analyzed. Weekday drinkers of 12 g/day or greater showed an increased risk in smokers. Alcohol consumption on weekends only in nonsmokers was inversely related. The influence of alcohol was greater for small-for-gestational-age (SGA) than non-SGA babies.

CONCLUSIONS

Alcohol consumption of 12 g/day or greater increased the risk for low birth weight, whereas lower consumption during weekends showed the opposite effect (mainly in nonsmokers).

Maternal alcohol consumption during pregnancy and physical outcomes up to 5 years of age: a longitudinal study

AIM

To examine whether alcohol exposure in pregnancy affects weight and head circumference (HC) at birth and 5 years, and whether these effects are independent of cigarette exposure in pregnancy and social disadvantage.

STUDY DESIGN

The Mater-University Study of Pregnancy (MUSP) involves a prospective cohort of 8556 mothers who were enrolled at first antenatal visit. The quantity and frequency of alcohol consumption in early and late pregnancy and a measure of binge drinking in early pregnancy were recorded. Weight and HC were measured on children seen at birth and at 5 years. Level of cigarette use in early pregnancy and maternal age and level of education and family income were also measured.

RESULTS

Light and moderate alcohol consumption in early or later pregnancy had no independent effects on weight or HC at birth or 5 years. Binge drinking in early pregnancy was not associated with restricted HC, and there was no effect modification by concurrent cigarette use in early pregnancy. An apparent effect of alcohol in late pregnancy on birth weight was due to confounding by cigarette use, with social risk being an independent predictor.

CONCLUSION

Alcohol ingestion up to moderate levels in pregnancy was not associated with deficits in either weight or HC at birth or at 5 years.

Effects of cumulative prenatal substance exposure and environmental risks on children's developmental trajectories

Examined the effects of cumulative prenatal substance exposure and cumulative environmental risk on the developmental trajectories of 278 infants, toddlers, and preschool children. Results indicated that both cumulative risk indexes were significantly correlated. Results also indicated that both indexes were related to decrements in developmental trajectories (intercept and slope) from 3 to 57 months of age. Both prenatal exposure and environmental risk added unique variance to the prediction of developmental level and rate of growth when entered after covariates (i.e., birth weight and sex). However, across a number of models with and without covariates, environmental risk accounted for more variance in developmental trajectories than did prenatal exposure. Implications are discussed.

The role of acetaldehyde in pregnancy outcome after prenatal alcohol exposure

It is not known why some heavy-drinking women give birth to children with alcohol-related birth defects (ARBD) whereas others do not. The objective of this study was to determine whether the frequency of elevated maternal blood acetaldehyde levels among alcoholics is in the range of ARBD among alcoholic women. MEDLINE was searched from 1980 to 2000 using the key words acetaldehyde, pharmacokinetics, and alcoholism for controlled trials reporting blood or breath acetaldehyde levels in alcoholics and nonalcoholics. Separately, using the key words fetal alcohol syndrome, epidemiology, prevalence, incidence, and frequency, articles were identified reporting ARBD incidences among the offspring of heavy drinkers. Of 23 articles reporting acetaldehyde levels in alcoholics, four met the inclusion criteria. Forty-three studies reported on the rate of ARBD in heavy drinkers, and 14 were accepted. Thirty-four percent of heavy drinkers had a child with ARBD, and 43% of chronic alcoholics had high acetaldehyde levels. The similar frequencies of high acetaldehyde levels among alcoholics and the rates of ARBD among alcoholic women provide epidemiologic support to the hypothesis that acetaldehyde may play a major role in the cause of ARBD.

Effect of exposure to a country liquor (Toddy) during gestation on lipid metabolism in rats

The objective of this study was to determine the effects of country liquor Toddy and its equivalent quantity of ethanol on lipid metabolism during gestation in rats. Female rats weighing an average of 125 g were exposed to Toddy (24.5 ml/body weight/day) and ethanol (0.52 ml/kg body weight/day) for 15 days before conception and throughout gestation. On the 19th day of gestation, altered liver function and hyperlipidemia was seen in both the treated groups. Altered liver function was evidenced by the increased activity of alcohol dehydrogenase, aldehyde dehydrogenase, glutamic oxaloacetic transaminase or aspartate amino transferase (GOT), glutamic pyruvic transaminase or alanine amino transferase (GPT) and gamma glutamyl transpeptidase (GGT). Hyperlipidemia was caused by increased biosynthesis and decreased degradation of lipids. The incorporation of 14C acetate in lipids and activities of HMG CoA reductase and lipogenic enzymes were elevated and activity of LPL and bile acids contents were decreased. Toddy treated rats were more severely affected than those receiving an equivalent quantity of ethanol. Toddy seemed to potentiate the toxicity induced by alcohol indicating the role of the nonethanolic portion. Hepatic functions were also affected.

Estimating the prevalence of fetal alcohol syndrome. A summary

Since the late 1970s, many studies have reported on the prevalence of fetal alcohol syndrome (FAS), alcohol-related birth defects (ARBD), and alcohol-related neurodevelopmental disorders (ARND). The three main types of research methods used in these studies are passive surveillance, clinic-based studies, and active case ascertainment. This article describes each of these methods, including their strengths and weaknesses, and summarizes the estimated prevalence of FAS produced by each of these approaches. The maternal risk factors associated with FAS and other alcohol-related anomalies include advanced maternal age, low socioeconomic status, frequent binge drinking, family and friends with drinking problems, and poor social and psychological indicators. Overall, the available literature points to a prevalence rate of FAS of 0.5 to 2 cases per 1,000 births in the United States during the 1980s and 1990s.

Socio-economic disparities in pregnancy outcome: why do the poor fare so poorly?

In this paper, we review the evidence bearing on socio-economic disparities in pregnancy outcome, focusing on aetiological factors mediating the disparities in intrauterine growth restriction (IUGR) and preterm birth. We first summarise what is known about the attributable determinants of IUGR and preterm birth, emphasising their quantitative contributions (aetiological fractions) from a public health perspective. We then review studies relating these determinants to socio-economic status and, combined with the evidence about their aetiological fractions, reach some tentative conclusions about their roles as mediators of the socio-economic disparities. Cigarette smoking during pregnancy appears to be the most important mediating factor for IUGR, with low gestational weight gain and short stature also playing substantial roles. For preterm birth, socio-economic gradients in bacterial vaginosis and cigarette smoking appear to explain some of the socio-economic disparities; psychosocial factors may prove even more important, but their aetiological links with preterm birth require further clarification. Research that identifies and quantifies the causal pathways and mechanisms whereby social disadvantage leads to higher risks of IUGR and preterm birth may eventually help to reduce current disparities and improve pregnancy outcome across the entire socio-economic spectrum.

Maternal smoking during pregnancy and infant head circumference at birth

Using the Swedish Medical Birth Registry, information on 1,362,169 infants born during 1983-1996 was analyzed in order to investigate the relation between maternal smoking during pregnancy and infant head circumference at birth. Infants of smoking mothers were at an increased risk to have head circumference <32 cm, and the adjusted odds ratios (OR) with 95% confidence intervals (CI) for any smoking, smoking <10 cigarettes per day, and smoking >/=10 cigarettes per day were: 1.65 (1.62-1.68), 1.52 (1.48-1.56), and 1.86 (1.81-1.92), respectively. A highly significant association between small head circumference for gestational age and maternal smoking was also found (ORs (with 95% CI) were for any smoking, <10, and >/=10: 1.58 (1.55-1.61), 1.48 (1.45-1.51), and 1.74 (1.70-1.79), respectively). For both outcomes, the observed dose-response effects were highly significant (P<10(-6)). Even more alarming was the finding that given a certain level of growth retardation, infants of smoking mothers were at an increased risk of small head circumference for gestational age compared to infants of non-smoking mothers (OR (with 95% CI) for any smoking adjusted for 'percentage of expected birth weight': 1.08 (1.06-1.10)). Given the evidence that maternal smoking specifically affects head growth, until contradictory evidence has been found, it seems reasonable to assume that maternal smoking during pregnancy affects brain development negatively.

Moderate alcohol consumption during pregnancy and the incidence of fetal malformations: a meta-analysis

To determine whether there is an association between moderate alcohol consumption in the first trimester of pregnancy and increased risk of fetal malformations, we conducted a literature search using Medline (1966-present), PsycLit (1974-1995), and EMBASE (1988-1995). The following inclusion criteria were used to select the studies to be evaluated: 1) pregnant women; 2) moderate alcohol consumption (> 2 drinks/week to 2 drinks/day); 3) case-control or cohort studies; 4) presence of an abstainer group (0 to 2 drinks/wk); 5) outcome measures include major or minor malformations; 6) papers published in the English language. The exclusion criteria were: 1) studies in which moderate alcohol consumption could not be confirmed; 2) case reports, and editorials. The Methods section of each study was examined independently by two blinded investigators with a third investigator settling any disagreement. The number of malformations in the abstainer and moderate alcohol consuming groups in two by two tables. Out of 24 studies which met the inclusion criteria, only seven had extractable data. The included studies evaluated 130,810 pregnancy outcomes, with 24,007 in the moderate alcohol group and 106,803 in the control group. An overall Mantel-Haenszel odds ratio showed that the relative risk for fetal malformations was 1.01 with 95% confidence limits of 0.94 to 1.08 and a chi-square for homogeneity of 8.26 (p = 0.220). Quality of the studies did not correlate with their showing negative or positive association. Moderate alcohol consumption during the first trimester of pregnancy is not associated with increased risk of fetal malformations.

Low-to-moderate gestational alcohol use and intrauterine growth retardation, low birthweight, and preterm delivery

PURPOSE

Heavy drinking during pregnancy is an established risk factor for fetal alcohol syndrome and other adverse perinatal outcomes. However, there is still debate as to the effects of low-to-moderate drinking during pregnancy.

METHODS

This prospective investigation was based on 2714 singleton live births at Yale-New Haven Hospital during 1988-1992. Alcohol drinking during pregnancy was evaluated with respect to intrauterine growth retardation (IUGR), preterm delivery, and low birthweight.

RESULTS

Mild drinking, defined as > 0.10-0.25 oz of absolute alcohol per day, during the first month of pregnancy was associated with a protective effect on IUGR (OR, 0.39; 95% confidence interval (CI), 0.20-0.76). Overall, drinking during month 1 of pregnancy suggested a curvilinear effect on growth retardation, with consumption of > 1.00 oz of absolute alcohol per day showing increased risk. Drinking during month 7 was associated with a uniform increase in the odds of preterm delivery; the ORs were 2.88 (95% CI, 1.64-5.05) for light drinking and 2.96 (95% CI, 1.32-6.67) for mild-to-moderate alcohol consumption.

CONCLUSIONS

Differences in the risk estimates for IUGR and preterm delivery may indicate etiological differences that warrant further investigation of these outcomes and critical periods of exposure. Low birthweight is not a useful neonatal outcome for this exposure because it is a heterogeneous mix of preterm delivery and IUGR. Despite the observed protective effects of mild drinking on IUGR, the increased risk of preterm delivery with alcohol use supports a policy of abstinence during pregnancy.

Newborn cerebrovascular responses after first trimester moderate maternal ethanol exposure in sheep

Fetal alcohol syndrome is one of the leading causes of mental retardation in the United States, but the pathogenesis of the associated brain damage is unknown. We tested the hypothesis that neonatal cerebrovascular responses to CO2 and/or hypoxia may be altered by moderate chronic maternal ethanol exposure early in gestation. We studied 26 newborn lambs (1-4 d old). Their mothers had received daily i.v. infusions of either ethanol (1 g/kg; ethanol concentration = 167 +/- 3 mg/dL; mean +/- SEM) or a similar volume of saline for 3 wk during the first trimester. In nine lambs, we studied cerebral responses to CO2 (saline, n = 4; ethanol, n = 5) and in 17 lambs, cerebral responses to hypoxia (saline, n = 7; ethanol, n = 10). Cerebrovascular responses to CO2 were not different between the groups. However, the cerebral vasodilatory response to hypoxemia was significantly attenuated in the ethanol lambs, such that cerebral O2 delivery was not maintained. During severe hypoxia (arterial PO2 = 30 mm Hg), cerebral blood flow increased 106 +/- 23% (mean +/- SEM) above baseline in the saline-treated group, but increased only 32 +/- 15% above baseline in the ethanol-treated group (p < 0.02). Similarly, cerebrovascular resistance in the saline group decreased 52 +/- 6% from baseline, but decreased only 16 +/- 11% in the ethanol group (p < 0.02). We conclude that moderate maternal ethanol infusion early in pregnancy attenuates neonatal hypoxic, but not CO2, cerebrovascular responsivity.

An update on incidence of FAS: FAS is not an equal opportunity birth defect

The incidence of Fetal Alcohol Syndrome is now estimated at 0.97 cases per 1,000 live births in the general obstetric population and 4.3% among "heavy" drinkers. The general incidence is more than 20 times higher in the United States (1.95 per 1,000) compared to Europe and other countries (0.08 per 1,000). Within the United States, the incidence at sites characterized by low socioeconomic status, and African American or Native American background are about 10 times higher (2.29 cases per 1,000) compared to sites with a predominant middle/upper SES and Caucasian background (0.26 per 1,000). Based on racial background, the number of pregnant women in the U.S. giving birth to FAS children is 2,043 per year; if based on socioeconomic status, the number is slightly higher 2,366. Although race and SES are confounded in the U.S. studies, an examination of U.S. and European studies suggests that the major factor associated with FAS is low SES rather than racial background.

Prenatal alcohol exposure, birthweight, and measures of child size from birth to age 14 years

OBJECTIVES

The purpose of the study was to examine the effect of prenatal alcohol exposure on offspring's weight, height, and head circumference from birth through 14 years of age.

METHODS

This longitudinal prospective study examined a cohort of approximately 500 offspring (oversampled for heavier drinkers and stratified for smoking from a population of 1529 women in prenatal care at the 5th gestational month) at birth; 8 and 18 months; and 4, 7, and 14 years of age. Covariates were examined by means of multiple regression. Birth size measures were also examined as predictors of 7-year neurodevelopmental outcomes.

RESULTS

Effects of alcohol were observed on weight, length, and head circumference at birth; these effects were not altered by adjustment for covariates including smoking. However, the birthweight effect is clearly transient: although alcohol effects remained observable at 8 months, they were not measurable thereafter through age 14 years.

CONCLUSIONS

In this population-based sample, neither birthweight nor any later size measure was as useful an indicator of the enduring effects of prenatal alcohol exposure as were certain neurodevelopmental outcomes.

Alcohol and the brain: setting the benefit/risk balance

This article reviews the literature and presents some unpublished data on the CNS effects of alcohol at doses not producing tolerance and dependence. The available evidence indicates that the effect of low doses of ethanol may qualitatively differ from those produced in animal models mimicking alcoholism. For example, rats exposed for two months to alcohol in drinking water at a concentration (3%) not inducing tolerance or dependence, as assessed by lack of withdrawal signs upon treatment suspension, appear to be less stressed in the two-way avoidance-learning tests. Accordingly, the treated rats perform better and learn faster than sucrose-fed controls, while this behavior is disrupted by high levels of ethanol intake. These initial observations suggest that discontinuity may exist between the effects of low and high doses of this substance and underscore the need to expand research on the effects of alcohol on the CNS to include the bottom end of the dose-response curve.

Smoking and drinking habits before and during pregnancy in Spanish women

STUDY OBJECTIVE

To investigate possible changes in smoking and drinking habits during pregnancy and to elucidate the sociodemographic factors associated with these changes in Spanish women.

DESIGN

A cross-sectional survey.

PARTICIPANTS AND SETTING

A total of 1004 pregnant women of between 12 and 18 weeks of gestation who were attending the antenatal clinic of the main regional hospital of Valencia (Spain) during 1989 were studied. All participants completed the study and only one eligible woman refused to participate when approached.

MEASUREMENTS AND MAIN RESULTS

Information was obtained by structured questionnaire (Euromac questionnaire), which included items on age, educational level, marital status, occupation, parity, previous and present smoking habits, and previous and present alcohol consumption. Women were asked about the consumption of cigarettes and alcohol for a typical week before they knew they were pregnant, and details of current consumption were obtained for the week before the interview. The number of drinks taken per week was later converted to the amount of absolute alcohol (in g). Sixty per cent of the women smoked and 72% drank alcohol before pregnancy. Forty eight per cent of smokers stopped smoking and 37% of drinkers stopped drinking alcohol during pregnancy. No sociodemographic factor showed an independent association with either smoking or drinking cessation. Only the number of cigarettes and the amount of alcohol consumed before pregnancy were identified as significant independent predictors for stopping.

CONCLUSIONS

Pregnant Spanish women seemed to stop smoking at about three times the rate found in Spanish women in the reproductive years. The sociodemographic variables usually associated with stopping smoking could not account for the high rate of quitting in these Spanish women, a rate higher than that in women from other developed countries. The high prevalence of smoking before pregnancy might explain not only the high rate of stopping smoking but also the absence of a well defined profile of "quitters". In our study, high levels of alcohol consumption were limited to a small group of pregnant women, and preventive efforts should be focused on this group.

Knowledge of FAS and the Risks of Heavy Drinking During Pregnancy, 1985 and 1990

Reducing the incidence of FAS to no more than 0.12 per 1,000 live births is a stated objective of the national agenda in Healthy People 2000. One step toward attaining this is by ensuring that all prospective mothers know what FAS is. Knowledge of FAS was elicited among respondents in two health surveys to determine how much women and men know about the risks of drinking during pregnancy, how knowledge levels have changed over time, and what the implications of these findings are with regard to reducing the level of FAS among newborns.

The consequences of prenatal substance use for the developing fetus, newborn, and young child

Although substance use has been a worldwide problem at all levels of society since ancient times, recent attention has been focused on the use of legal and illegal substances by the pregnant woman. Almost all drugs taken by the pregnant woman are known to cross the placenta and have some effect on the fetus. This article reviews the effects of the drugs most frequently used by pregnant women in the United States--nicotine, alcohol, marijuana, opiates, and cocaine--on the fetus and neonate; when possible, information regarding long-term medical problems is included.

Cigarette, alcohol, and coffee consumption and prematurity

We analyzed data from a survey of occupational and other factors in pregnancy to assess the effects of cigarette, alcohol, and coffee consumption on pregnancy outcome. The risk of low birth weight for gestational age was found to increase substantially with smoking. Occasional consumers of alcohol had a slightly reduced risk relative to total abstainers. In more frequent drinkers, there was a small increase in risk. Risk increased slightly with coffee consumption.