Drinking alcohol without knowing that you are pregnant may affect the fetus, but the effects of occasional drinking are usually minor. If a pregnant woman is in the early stages of pregnancy, pregnancy has not yet been detected, and the fetus is in a critical period of differentiation and development; if she drinks alcohol at this time, the alcohol can stimulate the embryonic cells, affecting the differentiation of the embryonic cells, and there is a risk of fetal malformations; the longer the duration of the drinking period, and the more the amount of alcohol consumed, the greater the effect on the fetus, and the impact of occasional alcohol consumption is usually not significant. If you are a pregnant woman in the middle or late stages of pregnancy, you have not yet found out that you are pregnant. Although the growth and development of the fetus has stabilized, alcohol consumption by pregnant women can increase the risk of intrauterine hypoxia in the fetus, and in serious cases, it can lead to intrauterine foetal death, which will have an effect on the fetus at this time, and it is not advisable for you to consume alcohol. Pregnant women should pay attention to their diet, and if they have special dietary needs, they need to be under the guidance of a medical professional, so as to avoid improper diet, which may lead to adverse consequences.