Liz Szabo

USA TODAY

Women of childbearing age should avoid alcohol unless they're using contraception, federal health officials said Tuesday, in a move to reduce the number of babies born with fetal alcohol syndrome.

“Alcohol can permanently harm a developing baby before a woman knows she is pregnant,” said Anne Schuchat, principal deputy director of the Centers for Disease Control and Prevention. “About half of all pregnancies in the United States are unplanned, and even if planned, most women won’t know they are pregnant for the first month or so, when they might still be drinking.

"The risk is real. Why take the chance?” Schuchat asked.

The CDC estimates 3.3 million women between ages 15 to 44 are at risk of exposing a developing fetus to alcohol because they drink, are sexually active and not using birth control. Even when women are actively trying to get pregnant, three in four continue drinking after they stop using birth control, according to the CDC report.

There is no known safe level of alcohol at any stage of pregnancy, according to the CDC. The American College of Obstetricians and Gynecologists recommends women abstain completely from alcohol while pregnant.

Alcohol use during pregnancy "can cause lasting physical, behavioral and intellectual disabilities that can last for a child’s lifetime," according to the CDC. These disabilities, known as fetal alcohol spectrum disorders, affect up to one in 20 school children, according to the CDC.

When pregnant women drink, "alcohol can quickly reach the fetus’s underdeveloped liver and brain through the placenta," said Mark DeFrancesco, the president of the obstetrician-gynecologist group.

Babies with fetal alcohol syndrome are more likely to be born small and to develop problems of the heart, kidney and brain, according to the CDC. Damage to the brain can lead to low IQ and learning disabilities, attention problems, hyperactivity, poor reasoning and judgement, as well as poor ability to communicate in social situations. All of these problems can lead to mental illness, substance abuse and other lifelong problems.

Alcohol use in pregnancy costs the USA $5.5 billion a year, according to the CDC.

Doctors "should routinely screen women regarding their alcohol use, both before and during pregnancy, and should provide support for women to stop use of alcohol when planning a pregnancy or when becoming pregnant," DeFrancesco said.

Some women who hope to become pregnant take prenatal vitamins, but don't think about their alcohol use, said Wanda Filer, president of the American Academy of Family Physicians. "Hopefully, this is the sort of report that will make people stop and think," Filer said.

Still, Filer acknowledged telling young women to completely abstain from alcohol could be a tough sell. Alcohol plays a role in many conceptions, after all, even among married couples.

"Some women will take this advice," Filer said, "and some will not."

The American Beverage Institute, a restaurant trade association, criticized the CDC's advice. "The CDC’s view on alcohol is incredibly puritanical," said Sarah Longwell, the group's managing director. "The more prohibitionist the agency’s stance, the less seriously the public will take its message."