There are individual differences in the probability of fetal malformations, and the average probability of fetal malformations in women who smoke is 2-3 times higher than that in non-smoking women. It is recommended that pregnant women quit smoking in a timely manner, stop smoking during pregnancy and preparation, and stay away from smoking environments. Cigarettes contain a large amount of nicotine, which can reach the fetus through the placenta and affect fetal growth and development, easily causing fetal malformations, such as fetal neural tube malformation, clubfoot, cleft lip and palate, etc. Smoking can also form carbon monoxide, which affects the combination of red blood cells and oxygen, reducing the amount of placental blood circulation, resulting in reduced oxygen supply, causing intrauterine distress, and even causing premature birth and miscarriage. The early stage of pregnancy is a critical period for the formation and differentiation of fetal organs, and there is a greater chance of fetal malformations being affected by smoke during this period. Therefore, while quitting smoking, you should take folic acid during the first 3 months of pregnancy to prevent fetal neural tube development malformations, and undergo Down’s syndrome screening and 4D ultrasound examination at 16 and 24 weeks of pregnancy respectively to rule out fetal malformations. If the fetus is already abnormal, it is recommended to follow medical advice and terminate the pregnancy if necessary.