Having sex after drinking alcohol may affect the quality of the sperm or eggs, and if pregnancy occurs it may have an adverse effect on the fetus and affect fetal development, but it is not clear how much. Generally speaking, if pregnancy is discovered after occasional, small amounts of alcohol consumption, there may be no significant effects on the fetus and there is usually no need to worry too much. At this time, pregnant women are advised to seek medical attention for relevant tests to monitor the development of the fetus. If a man has a long history of alcohol consumption or alcohol abuse before pregnancy, it can affect the quality of the man’s sperm, which can easily lead to fetal development delays or even malformations. If a woman has a longer history of alcohol consumption or alcohol abuse, alcohol can easily cross the placenta and cause damage to the developing embryo or fetal brain and other organs, which can have irreversible effects on the fetus, especially in the early stages of pregnancy, excessive and long-term alcohol consumption can easily lead to fetal alcohol syndrome, making the fetus develop malformations, organ development defects, intellectual backwardness and neurological dysfunction, etc. The neurological damage is more serious. Among them, the damage to the nervous system is more serious and may even cause stillbirth, miscarriage and premature birth. In addition, long-term stimulation of alcohol may cause abnormalities in the liver, digestive function, central nervous system, and cardiovascular system of women. The poor functioning of the mother’s organs may also lead to fetal growth retardation, such as low weight, small head circumference, and poor visual and auditory development, due to the inability of the mother’s organs to meet the normal developmental needs of the fetus. If fetal abnormalities are found, the pregnancy should be terminated if necessary. From the perspective of eugenics, you should stop smoking and drinking in the first three months of pregnancy preparation, and if you get pregnant after drinking accidentally, pregnant women should strengthen maternity checkups and pay attention to Down’s syndrome screening and 4D ultrasound in the middle and late stages. And during pregnancy, you should also develop good habits, avoid smoking in addition to alcohol, go to bed early and wake up early, strengthen nutrition, take in some meat, eggs and dairy foods appropriately, and take folic acid and calcium supplements as required by your doctor, and exercise appropriately to benefit the development of the fetus.