Vaccines can be roughly divided into two categories, “inactivated vaccines” and “non-inactivated vaccines”. For pregnant women, inactivated ones can be given, while attenuated or live vaccines cannot be given. Inactivated vaccines mean that the microorganisms in the vaccine have been killed by chemical or physical means, but are sufficient to give the body immunity. Vaccines such as tetanus, for example, can be used during pregnancy. Attenuated or live-attenuated vaccines, which are made of microorganisms with weakened pathogenic power, are the only ones that keep “alive” enough for the body to develop immunity. Measles vaccine and rubella vaccine are among such vaccines and are prohibited during pregnancy. These vaccines are not prohibited during pregnancy but are recommended instead During pregnancy, some viral or bacterial infections can affect the development of the fetus and even threaten the life of the baby. For this reason, I generally recommend the following two vaccines. 1. Influenza vaccine Influenza vaccine mainly prevents infection with certain sub-strains of the seasonal influenza virus. If you are pregnant during the high influenza season, such as between November and March, it is recommended to receive the influenza vaccine shot regardless of whether the pregnancy is in early, middle or late pregnancy, as it is mostly inactivated vaccine, which is safe and effective. However, it is important to note that the flu vaccine inhaled via the nose is a live vaccine and should be avoided according to the principles we just mentioned. If you are preparing for pregnancy during the high season of influenza and are not pregnant, the two flu vaccines mentioned above can be used during the preparation stage. 2.Diphtheria vaccine Regardless of when the vaccine was given before pregnancy, it is recommended to be given again during pregnancy. This vaccine can prevent diphtheria, acellular pertussis and tetanus. The best time to get vaccinated is between 27 and 36 weeks of pregnancy, so that both the baby and the mother can be protected. What are the vaccines that are contraindicated during pregnancy? The following vaccines are live attenuated virus vaccines and are contraindicated during pregnancy: Measles vaccine Rubella vaccine Mumps vaccine Varicella vaccine BCG vaccine In addition, there is no clear evidence that human papillomavirus (HPV) vaccination during pregnancy is harmful to the fetus. However, because the research data are not sufficient, it is recommended that vaccination not be continued if pregnancy is detected. However, those who have been vaccinated during previous pregnancies do not need to terminate their pregnancy. Can these vaccines be administered during pregnancy? 1. These vaccines can be prophylactically administered to pregnant women exposed to high risk (1) Hepatitis B vaccine is a recombinant vaccine and can be administered if exposed to high risk. (2) Hepatitis A vaccine is an inactivated virus vaccine and can be administered if exposed to high risk. (3) Pneumococcal vaccine is an inactivated bacterial vaccine. The indications for vaccination do not change due to pregnancy, and the vaccine is only used for high-risk groups. (1) Meningococcal vaccine is an inactivated bacterial vaccine, and the indications for vaccination do not change due to pregnancy; vaccination is recommended during pregnancy in case of an outbreak. (2) Typhoid vaccine is an inactivated bacterial vaccine and is not recommended during pregnancy unless there is close, continuous exposure or travel to endemic areas. (3) These vaccines can be given during pregnancy in case of unexpected conditions (1) Rabies vaccine inactivated virus vaccine for prevention after being bitten or scratched by dogs or other animals can be given during pregnancy. (2) Tetanus toxoid is used for the prevention of contaminated wounds, and can be inoculated during pregnancy. (4) In addition, there is a class of biological agents, which cannot be called vaccines, but can also be used for disease prevention (1) Rabies immunoglobulin is a specific immunoglobulin for post-exposure prophylaxis, and can be inoculated during pregnancy. It is used in combination with rabies vaccine. (2) Tetanus immunoglobulin is a specific immunoglobulin used for post-exposure prophylaxis and can be given during pregnancy. It is used in combination with tetanus toxoid. (3) Varicella immunoglobulin is a specific immunoglobulin that can be considered for healthy pregnant women exposed to varicella to protect the mother rather than to prevent congenital infection of the fetus. What vaccines can be given to breastfeeding women? Any vaccine can be administered while breastfeeding. Breastfeeding does not affect vaccines and vaccines do not affect breast milk. What do women who are preparing for pregnancy need to know about vaccinations? If the vaccines given to women in preparation for pregnancy are vaccines that are contraindicated during pregnancy, then it is recommended that the vaccine be given one month before pregnancy. Finally, I would like to emphasize that there is no evidence that vaccination during pregnancy causes damage to the health of the fetus, and even if a live virus vaccine that is contraindicated is administered, the effect on the fetus is unknown, so it is not recommended to easily terminate a pregnancy just because you have received that type of vaccine. Of course, if you already know you are pregnant, it is safe to avoid vaccinations that are currently contraindicated during pregnancy.