Alcohol is directly toxic to the fetus and causes birth defects.
Women who consume two or more drinks per week while pregnant have a higher risk of spontaneous abortion, which is the expulsion of a dead fetus. Most spontaneous abortions occur during the second trimester. Drinking while pregnant also increases the risk of stillbirth, or the birth of a dead infant. Stillbirths can occur after heavy drinking in the last three months of pregnancy. Drinking alcohol at this stage of pregnancy lessens the amount of oxygen delivered to the developing child.