Smoking is not recommended during preparation for pregnancy. Couples are not allowed to smoke during preparation, pregnancy and delivery. Cigarettes have a component, nicotine, which is an alkaloid that stimulates the central nervous system and also causes vasoconstriction of the placenta, which affects the blood circulation of the fetus in the womb, affecting the growth and development of the fetus, leading to miscarriage, fetal malformation, and so on. Preparation for pregnancy is a critical period in the pregnancy stage, a crucial step to ensure the normal formation and implantation of a fertilized egg. If you smoke during this period, it may affect the development and implantation of the fertilized egg, and may even affect the subsequent development of the fetus. In order to ensure the safety of the mother and fetus, it is recommended not to smoke during the preparation period.