Alcohol Abuse During Pregnancy is dangerous. Alcohol can have a number of harmful effects on the baby. The baby can be born mentally retarded or with learning and behavioral problems that last a lifetime. We don’t know exactly how much alcohol is required to cause these problems. We do know, however, that these alcohol-related birth defects are 100- percent preventable, simply by not drinking alcohol during pregnancy. The safest course for women who are pregnant or trying to become pregnant is not to drink alcohol at all.