Drinking During Pregnancy

There is probably no other issue in the debate about health and alcohol that is as contentious as drinking during pregnancy. Most physicians and health care agencies advise women that if they are pregnant or trying to get pregnant, they should reduce their alcohol intake much as possible and most advise eliminating alcohol completely. The American Academy of Pediatrics and the American College of Obstetricians and Gynecologists recommend that pregnant women avoid alcohol entirely. In 1982, the FDA suggested that alcoholic beverages should carry warning labels, and in 1988 Senator Strom Thurmond, who had been campaigning for a warning since 1967, introduced a bill to the Senate which in final form was signed into law in 1989.

DrinkWise Australia is partnering with The Winemakers Foundation to adopt health warnings on wine labels including risks to pregnant women of drinking alcohol. The organizations are also providing brochures to retailers that contain the message, “It is safest not to drink alcohol while pregnant.”

An excellent article on the subject, “Light Drinking During Pregnancy: What Recent Studies Do - and Do Not - Tell Us,” by Evan Dawson, is published in the online magazine, Palate Press, February 19, 2012 (www.palatepress.com/2012/02/wine/light-drinking-during-pregnancy-what-recent-studies-do-and-do-not-tellus/).

Alcohol is able to passes efficiently and quickly through the placenta from the mother’s bloodstream into the baby’s bloodstream and the blood alcohol concentration (BAC) of the fetus becomes equal to or greater than the BAC of the mother. Since the fetus cannot metabolize alcohol like an adult, its BAC remains high for a longer period. For that reason, women who decide to have wine during pregnancy should consume minimal amounts and always sip it slowly with food to avoid a rapid rise in blood alcohol levels.

The University of Queensland reports that 80 percent of Australian women consume alcohol at low-tomoderate levels during pregnancy, compared to 12 percent in Sweden and 10 percent in the United States.

Moderate Alcohol Intake During Pregnancy and Risk of Fetal Death Int J Epidemiol 41 (2) April 2012 A large Danish pregnancy cohort was studied and it was found that even low amounts of alcohol consumption during early pregnancy increased the risk of spontaneous abortion substantially indicating the fetus is particularly susceptible to alcohol exposure early in pregnancy. There was no increased risk for fetal death after the first trimester (16 weeks) of pregnancy.

Safety Concerns Regarding Binge Drinking In Pregnancy: A Review Birth Defects Res A Clin Mol Teratol 94 (8) August 2012 The evidence in humans is not conclusive, but the incidence of binge exposures in pregnancy is high and women inadvertently exposed to a single binge episode of alcohol early in the first trimester before pregnancy recognition can be reassured that the risks for adverse effects in their baby are likely low if they are able to discontinue the use of alcohol for the during of the pregnancy. There still remains some residual fetal risk.

Estimated Number of Preterm Births and Low Birth Weight Children Born in the United States Due to Maternal Binge Drinking Matern Child Health J June 2012 ahead of print Maternal binge drinking contributed significantly to preterm birth and low birth weight across sociodemographic groups with women ages 40-44 with the highest adjusted binge drinking rate and highest preterm birth due to maternal binge drinking.

Fetal Exposure and IQ at Age 8: Evidence from a Population-based Birth-cohort Study PLOS One November 14, 2012 This report presents evidence from a population-based birth-cohort study. Data was collected from 4,000 mothers and offspring born in the 90s. Relatively small levels of exposure to alcohol while in womb can influence a child’s IQ. The study used genetic variation not influenced by lifestyle or other factors to investigate the effects of moderate drinking during pregnancy. Four genetic variants in alcohol-metabolizing genes among the children were strongly related to lower IQ at age 8. Variations in the genes that encode the enzymes that convert ethanol to acetaldehyde lead to differences in the ability to metabolize ethanol. ‘Slow metabolizers’ may have higher alcohol levels that persist longer than in ‘fast metabolizers.” No effect among mothers who abstained during pregnancy was observed, even if they had alcohol-sensitizing genes. Heavy drinkers were not included in this study. The associations between the child’s genotype and outcome were only present among those whose mothers reported drinking alcohol in moderation during pregnancy. Even small amounts of alcohol in utero can affect future cognitive outcomes and the authors of the study recommend avoidance of alcohol when pregnant. This study was on white European women and used self-reporting so use of alcohol may have been underreported.

A Longitudinal Study of the Long-Term Consequences of Drinking During Pregnancy: Heavy In Utero Alcohol Exposure Disrupts the Normal Processes of Brain Development J of Neuroscience 32 (44) October 31, 2012 Using MRI to measure cortical volume change longitudinally in a cohort of human children and youth with prenatal alcohol exposure and a group of unexposed control subjects, this study found that the normal processes of brain maturation are disrupted in individuals whose mothers drank heavily during pregnancy.

The Effects of Low to Moderate Alcohol Consumption and Binge Drinking in Early Pregnancy on Executive Function in 5-year-old Children BJOG 119 (10) September 2012 This study did not observe significant effects of low to moderate alcohol consumption during pregnancy on executive function at the age of 5. Weak or no consistent association between maternal binge drinking and executive functions were observed. (Executive functions are cognitive processes such as planning, working memory, and problem solving)

The Effects of Low to Moderate Alcohol Consumption and Binge Drinking in Early Pregnancy on Selective and Sustained Attention in 5-year-old Children BJOG 119 (10) September 2012 This study suggested an effect of maternal consumption of nine or more drinks per week on attention functions in children, but the study detected no effects of maternal binge drinking.

The Effects of Alcohol Binge Drinking in Early Pregnancy on General Intelligence in Children BJOG 119 (10) September 2012 No association was found between binge drinking during early pregnancy and child intelligence compared to children of mothers with no binge episodes.

The Effects of Low to Moderate Prenatal Exposure in Early Pregnancy on IQ in 5-year-old Children BJOG 119 (10) September 2012 Maternal consumption of low to moderate quantities of alcohol during pregnancy was not associated with the mean IQ score of preschool children. However, the conservative advice for women continues to be to avoid alcohol use during pregnancy.

The Effect of Different Alcohol Drinking Patterns in Early to Mid Pregnancy on the Child’s Intelligence, Attention, and Executive Function BJOG 119 (10) September 2012. 1628 women and their children sampled from the Danish National Birth Cohort. A combined analysis of estimated effects of maternal average weekly alcohol consumption, and any binge drinking, in early to mid pregnancy, showed no statistically significant effects arising from average weekly alcohol consumption or any binge drinking either individually or in combination replicating the findings from separate analyses of each outcome variable. The children of mothers who had up to eight drinks a week were just as smart as their peers born to abstaining mothers. Drinking more than nine drinks per week was associated with lower attention spans among children. Children of mothers who had a binge episode early in pregnancy (before realizing they were pregnant) performed just as well on mental tests. The authors of the study say that the results suggest that expectant mothers can have a drink now and then without serious concern. However, no safe level of drinking during pregnancy has been established.