The third dose of the vaccine does not affect pregnancy preparation, but it cannot be administered if you are already pregnant. There is no authoritative literature or clinical cases that can prove that the vaccine affects sperm and egg activity or embryo development, and therefore cannot prove that the vaccine affects pregnancy preparation. After the third dose of the vaccine, you can still prepare for pregnancy normally and do not need to worry too much. However, it is recommended that a progesterone test be performed before the third dose of the vaccine to determine if you are pregnant. Pregnancy is a clear contraindication to vaccination, and people who are pregnant should not be vaccinated. Also, consult with the staff at the vaccination center before vaccination, and follow the staff’s guidelines after introducing your situation in detail.