According to the Diagnostic and Statistical Manual of Mental Disorders alcohol abuse is a psychiatric diagnosis describing the use of alcoholic beverages despite negative consequences.

The U.S. Surgeon General has released advisories in 1981 and again in 2005 urging women who are pregnant or may become pregnant to abstain from alcohol. The damage caused by prenatal alcohol abuse includes a range of physical, behavioral, and learning problems in babies.

Babies most severely affected have what is called fetal alcohol syndrome. These babies may have abnormal facial features and severe learning disabilities. Babies can also be born with mild disabilities without the facial changes typical of fetal slcohol syndrome.

Women giving birth to children with fetal alcohol syndrome also have a higher risk of early mortality.
A study from the Telethon Institute for Child Health Research has revealed the consequences of alcohol abuse on pregnancy.

It shows the effects of alcohol abuse and demonstrates that heavy and binge levels of alcohol during pregnancy increases the risk to the baby, even if drinking is stopped in the first three months of pregnancy. The findings are sobering and should act as a deterrent to alcohol abuse during pregnancy.

The study investigated the relationship between prenatal exposure to alcohol and the effects on fetal growth and preterm birth.

A random sample of 4,719 women who gave birth in Western Australia between 1995 and 1997 took part in a survey. Data such as how often participants drank alcohol, the amount of alcohol consumed in each occasion and the types of alcoholic beverage consumed were collated.

The research team from the Institute with the National Perinatal Epidemiology Unit at the University of Oxford found that, on average, levels of alcohol intake decreased from the pre-pregnancy period to the second and third trimester.

The incidence of preterm birth was highest amongst women who binge drink (9.5%) or drink heavily, even if the mother stopped drinking prior to the second trimester (13.6%), compared with less than 6% in women who did not drink during pregnancy. There were 2.3-fold increased odds of preterm birth in women who drank heavily in early pregnancy but then stopped after taking into account maternal smoking, drug use, socioeconomic status and maternal health. Researchers suggest that a possible reason why this occurs is because the cessation of alcohol abuse before the second trimester may trigger a metabolic or inflammatory response resulting in preterm birth.

Although there was no difference in outcomes for women who drank low levels of alcohol during their pregnancy and those that abstained, the safest choice is to stop drinking alcohol during pregnancy. Drinking at any level during pregnancy should be regarded as a risk factor for the mother as well as for offspring.

Researchers noted a link between smoking and alcohol consumption; they found women who smoked during pregnancy were less likely to abstain from alcohol at any time during their pregnancy than non-smokers. Over one quarter (27.7%) of women who drank in late pregnancy also smoked, compared with 19% of women who had abstained from alcohol during pregnancy. Other factors associated with late term pregnancy drinking include: a maternal age of 30 years and above, higher income, and use of illicit drugs.

Institute researcher Colleen O'Leary said “Our research shows pregnant women who drink more than one to two standard drinks per occasion and more than six standard drinks per week increase their risk of having a premature baby, even if they stop drinking before the second trimester”.  A standard drink in this analysis is the Australian standard 10gm of alcohol, eg 100ml of wine.

The risk of preterm birth is highest for pregnant women who drink heavily or at binge levels, meaning drinking more than seven standard drinks per week, or more than five drinks on any one occasion.

Health professionals should routinely screen pregnant women and all women of child bearing age for alcohol abuse or use. It's important that women should be given information about the possible risks to the baby from alcohol exposure during pregnancy.

Another recent study has demonstrated that alcohol consumption during pregnancy can alter the microstructural integrity of developing fetal cerebral white matter in the frontal and occipital lobes of the brain. Jeffrey R. Wozniak, assistant professor of psychiatry at the University of Minnesota had this to say, "As the technology improves, it seems clear that increasingly subtle forms of brain damage and cognitive deficits will become evident among those exposed to lower levels of alcohol. In other words, one cannot define a 'safe' level of alcohol exposure for the fetus."
References:
1. O'Leary C, Nassar N, Kurinczuk J, Bower C. Impact of maternal alcohol consumption on fetal growth and preterm birth. BJOG 2009;116:390.
2. American Psychiatric Association.
3. The National Institute on Alcohol Abuse and Alcoholism.
4. Berg JP, Lynch ME, Coles CD. Increased mortality among women who drank alcohol during pregnancy. Alcohol. 2008 Nov;42(7):603-10. PMID: 18835595.
5. Brian C. Schweinsburg, et al. Characterization of White Matter Microstructure in Fetal Alcohol Spectrum Disorders. Alcoholism: Clinical & Experimental Research.
6. Image by brapps.