The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.

What are the issues of vaccination and pregnancy?

Over the past several decades, both weakened live attenuated (living but weakened) vaccines and various types of non-living vaccines have been produced to confront numerous diseases. Pregnancy is a situation that requires researchers and healthcare providers to assess the needs for particular vaccines in terms of the benefits and risks to the baby as well as to the mother. In terms of immunization status, the ideal situation is for a woman to be up to date with all vaccines prior to getting pregnant, as there as some infectious diseases one in particular called rubella — which can do permanent, severe harm to your future baby early in pregnancy. Rubella is part of a three-component vaccine that protects against not just rubella, but also two other diseases measles and mumps and it must be given prior to pregnancy, not during. However, a booster shot for another combination vaccine, called Tdap, should be given during pregnancy in order to protect the fetus from a condition called pertussis, also called whooping cough. Similarly, influenza vaccination, must be given during pregnancy if the timing of your pregnancy is such that the flu season is approaching.

Although most people make an effort to stay up to date on their vaccines, there is a great deal of information floating around against vaccines, some of it dead wrong. First and foremost among incorrect information is that being spread by a movement of individuals who are opposed to vaccines in all forms, a movement whose propaganda you may confront in the course of your pregnancy as its adherents often attempt to dissuade pregnant women against protecting themselves and their babies through vaccination.

What is vaccination during pregnancy given to prevent?

There are numerous vaccines, given to prevent numerous illnesses. Many of these vaccines you need to receive prior to becoming pregnant, or prior to attempting to become pregnant. One such example is the vaccine for measles, mumps, and rubella (MMR). This is given to prevent the three named diseases in the mother herself, but also to prevent congenital rubella syndrome, a very serious set of birth defects that can occur in infants born to mothers who are infected with rubella virus while pregnant, or just before becoming pregnant. However, since MMR is a live vaccine, health authorities recommend against giving it to women who are pregnant, or who are trying to become pregnant. 

On the other hand, some vaccines must be given during pregnancy. Influenza vaccine is one example, and it is given to prevent influenza disease, which normally strikes about 20 percent of the population of the United States each year. Since flu is seasonal and different each year, and since pregnancy lasts 40 weeks, chances are that youll need to receive your influenza vaccination during pregnancy in order to be immunized on time for the flu season. Frequently there are many fatalities from flu, sometimes even in young people, and every year large numbers of people are hospitalized because of flu. During pandemics (huge outbreaks affecting humans throughout the planet) up to 50 percent of people can be infected. The number of pregnant women developing flu corresponds roughly to the number of people overall, so about 20 percent of pregnant women develop the flu, but the proportion of people requiring hospitalization is higher for pregnant women compared with the general population. 

Pregnancy is the time when you are recommended to receive a booster Tdap shot, a vaccine against tetanus, diphtheria, and pertussis, also called whooping cough. In the case of pertussis, you and your future infant are at particular risk. This vaccine is most effective if given 19-37 weeks into pregnancy.

How do vaccines work?

There are many different types of vaccines, but all work by teaching your immune system to recognize a particular type of virus, cells of a particular bacterial strain, or a toxin that is produced by a disease causing bacterial species.

If I receive a vaccine during pregnancy, can it harm my baby?

The vaccines that are administered during pregnancy have been studied and found to be beneficial, rather than harmful. There is concern about live vaccines, as they present a theoretical risk to the developing baby. Nevertheless, if you receive a live vaccine before knowing that you are pregnant, the recommendation of health authorities is generally to proceed with the pregnancy as normal, as your baby will most likely be fine.

If I receive a vaccine and become pregnant, what should I do?

Continue with your pregnancy as normal.

If I am given a vaccine, can I safely breastfeed my baby?

Yes. All of the vaccines that are recommended during pregnancy are also safe if given while you are breastfeeding.

If I am given a vaccine, will it be more difficult to get pregnant?

Routine vaccines should not affect your fertility negatively.

If I am given a vaccine, what should I know?

You should know that there are no live agents in the inactivated influenza vaccine, nor in Tdap, so there is no concern about infection of the developing baby.

If I am taking any vaccine, what should I know?

Always consult a health care professional about the risks associated with getting immunized, and the risks of not getting immunized, with respect to specific infectious diseases to determine what is best for you and your baby. Always consult your doctor before you accept, or refuse any vaccine offered to you during your pregnancy and while you a nursing.

You may find Pregistry’s expert reports about  a variety of vaccines here, and reports about the various medications used for infections here.   Pregistry also offers blog posts about vaccines here. Additional information can also be found in the resources at the end of this report. 

Resources for vaccines in pregnancy:

For more information about vaccination during and after pregnancy, contact (800-994-9662 [TDD: 888-220-5446]) or check the following links:


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General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.