Public announcements have made it clear that drinking alcohol while pregnant may cause developmental problems for the baby. Alcohol abuse in families may also affect a teen’s ability to make good decisions.

Two new studies, covering different aspects of alcohol’s affect on children, were released today and continue to support how damaging it can be.

One study revealed that any drinking during pregnancy increases the odds of fetal alcohol syndrome, but the risk to the fetus is highest if a pregnant woman drinks during the second half of her first trimester of pregnancy

The second study examines adolescents who grew up in families with a history of alcoholism and their ability to make good decisions.

Pregnancy and alcohol:

In the pregnant mom study, researchers found that for every one drink per day increase in alcohol intake during the second half of her first trimester, a woman’s baby was 25 percent more likely to have an abnormally shaped lip, 12 percent more likely to have a smaller-than-normal head and 16 percent more likely to have low birth weight. All of these are early signs of fetal alcohol syndrome.

Because alcohol easily passes the placental barrier and the fetus is less equipped to eliminate alcohol than its mother, the fetus tends to receive a high concentration of alcohol, which lingers longer than it would in the mother's system.

"The take-home message is that there's not a low threshold level below which drinking alcohol doesn't raise the risk," of fetal alcohol syndrome, said study author Dr. Christina Chambers of the University of California, San Diego. "This supports the surgeon general's recommendation that drinking be avoided entirely."

The study involved 992 participants who were recruited when they called a California help line that answers questions on substances that could be harmful during pregnancy.

The women called the hotline between 1978 and 2005 were asked if they would participate in a follow-up study on levels of alcohol consumption throughout pregnancy. The women who answered yes were then contacted by phone for follow-up and their infants were screened after birth with a full physical exam.

"You're dealing with an issue here in which it's really hard to get good information on both exposure and outcomes. Most kids don't get diagnosed until they're in school and having learning difficulties," Chambers said.

Not surprisingly, the researchers found that higher alcohol consumption of a mother during pregnancy was linked with a higher chance of a baby having physical characteristics associated with fetal alcohol syndrome, including abnormal head size and altered shape of the eyes and lips. Such symptoms suggest the presence of related neurological problems.

Researchers also mentioned that other factors can influence whether a woman who drinks during pregnancy will have a baby with fetal alcohol syndrome.

"Even if you find 10 women who drink a quart of vodka a day, maybe only five of those babies will have full-blown fetal alcohol syndrome, because there are other factors that influence the risk," Chambers said.

Those factors could include diet, body fat levels, genetic differences, or other environmental exposures, said Ed Riley of San Diego State University, who also studies prenatal exposure to alcohol.

Riley said the new study adds weight to the argument against drinking any alcohol during pregnancy, and emphasized that the new study showed that any alcohol consumption led to an increased risk. "They showed no threshold effect," he said, "so the more you drank, the greater probability of having an adverse outcome."

Teens from a family with a history of alcoholism:

U.S. researchers have found that teens with a family history of alcoholism experience weaker brain response when presented with risky verses safe decision-making.

Here’s how the study was conducted.

The researchers used functional magnetic resonance imaging to examine brain responses of the participants during a so-called “Wheel of Fortune decision-making task,” which presented risky versus safe probabilities of winning different amounts of money.

"While our study found adolescents with a family history of alcoholism did not perform significantly differently on the Wheel of Fortune task compared to the adolescents with a negative family history of alcoholism, we found two areas of the brain that responded differently," Nagel said in a statement.

These areas were in the prefrontal cortex and cerebellum, both of which are important for higher-order day-to-day functioning, such as decision-making. In these brain regions, adolescents with a family history of alcoholism showed weaker brain responses during risky decision-making compared to their peers without a family history of alcoholism.

The findings found those with a family history of alcoholism demonstrated atypical brain activity while completing the same task as those without a family history of alcoholism.

"Therefore, differences in brain activity may impact the ability of individuals family history of alcoholism to make good decisions in many contexts, and in particular may facilitate poor decision-making in regards to alcohol use," Nagel said. "Taken together with other studies on youth family history of alcoholism, these results suggest that atypical brain structure and function exist prior to any substance use, and may contribute to an increased vulnerability for alcoholism in these individuals."

More and more studies support the idea that alcoholism and pregnancy, as well as alcohol abuse in families, can leave long-term negative side effects. So if you see a pregnant mother drinking alcohol, you might gently remind her that her baby is drinking too.

Both findings were published in the journal Alcoholism: Clinical and Experimental Research.