Everything you need to know about vaccines and pregnancy
Which vaccines are recommended during pregnancy? Why? And most importantly – when?
This is a very important topic that is indirectly related to pediatrics.
Since we’re already on the subject, I’ll share a secret with you. In the past, my dream was to open a clinic for infectious diseases in pregnancy, with an emphasis on vaccines during pregnancy. I even considered the idea of offering couples an appointment at the clinic as a wedding gift…
I share this all with you to emphasize that ideally, and if permittable, the thought process about diseases and vaccines in pregnancy should take place before conception. In addition, it is important not only think about the mother’s vaccine status, but also try to optimize the father’s vaccine status.
To summarize, I would like to state that the best-case scenario would be if a couple planning for a child would see their family physician six months before the woman plans to become pregnant, bring with them both of their vaccine records, and create a joint vaccine program.
Please note, this is not a comprehensive summary of all the potential infectious diseases in pregnancy, but only the ones that can be prevented through vaccines. I recommend continuing your reading to cover the prevention of two additional important diseases during pregnancy – Cytomegalovirus infection (summarized in the link here), and Toxoplasma (in the link here).
Here are some key points that are important for you to understand:
Why a woman should consider getting vaccinated during pregnancy
There are several reasons:
Direct protection of the pregnant mother – pregnancy is a medical condition that puts the mother at higher risk for infectious diseases and various complications. Some infectious diseases are more severe during pregnancy, so it is important to protect the pregnant woman from as many infections as possible.
Direct protection of the fetus – the pregnant mother transfers antibodies against various infectious diseases to her child, primarily during the third trimester and also through breastfeeding afterwards. For example, vaccinating a pregnant woman against Pertussis will cause her to develop antibodies against the disease. These antibodies are then transferred passively to the fetus, offering protection against infection for a certain period of time.
Protection against congenital syndromes – vaccines exist for a number of infectious diseases that may occur during pregnancy, as a maternal infection with any of these could lead to unpleasant congenital syndromes in the fetus. Examples include Rubella and Varicella.
Prevention of premature delivery – many of the infectious diseases that can occur during pregnancy, in fact, all febrile diseases, have been associated with premature delivery. If we can prevent this, then all the better.
Are all vaccines safe during pregnancy?
No. Pregnant women should avoid receiving live-attenuated vaccines. Therefore, it is recommended to administer vaccines in advance, prior to pregnancy, whenever possible.
Which diseases have vaccines that all pregnant women should receive?
See more details about each one of these diseases below.
Hepatitis B.
Chickenpox (varicella).
Rubella (and measles and mumps too).
Influenza.
Hepatitis B vaccine during pregnancy
Hepatitis B is the only disease for which almost universal screening during pregnancy is conducted in most countries. Hepatitis B vaccination has been available since the early 1990s and is part of the routine childhood vaccination schedule in many countries. However, some individuals have not been vaccinated, while others may have contracted the infection and become chronic carriers without being aware of it. Therefore, any woman without documented proof of receiving three doses of the Hepatitis B vaccine, or whose blood tests do not show antibodies at a sufficiently protective level, should begin a new series of vaccinations. While it is preferable to get vaccinated before becoming pregnant, these vaccinations are also safe to receive during pregnancy.
Pertussis (and Tetanus and Diphtheria while we’re at it)
Getting Pertussis during pregnancy is a horrible experience. I have witnessed, firsthand, women who have had their ribs broken from severe coughing fits. This makes it all the more important to protect women from this infection.
Equally important is the goal of vaccinating women during pregnancy to protect their infants from Pertussis. Infection with Pertussis in infants under 6 months old can be extremely severe. In most countries, infants receive their first Pertussis vaccine dose at 2 months (followed by doses at 4 months, 6 months, and 1 year). However, the majority of infants cannot develop antibodies quickly enough in the first six months to provide adequate protection against the infection. Research has shown that vaccinating pregnant women during the third trimester reduces the prevalence of infection in infants after birth. This is because the mother is less likely to become infected and transmit the disease to her child, and also because of the passive transfer of antibodies I mentioned earlier.
In most countries, the Pertussis vaccine is recommended for pregnant women between gestational weeks 27 and 36 during each pregnancy, regardless of the time passed since the previous pregnancy. I suggest receiving the vaccine around gestational week 27 to maximize the transfer of antibodies to the baby and to provide protection for the mother during labor.
How are Tetanus and Diphtheria related to Pertussis? The vaccine commonly given is a combination of Tetanus, Diphtheria, and Pertussis vaccines. There is no harm in receiving a Tetanus vaccine every few years, but there is a slight disadvantage—each subsequent injection tends to cause more pain at the site. It’s not the end of the world, though.
Chickenpox (Varicella)
Most of us had Chickenpox during childhood, but the prevalence of the disease has been steadily decreasing. The current generation of children has received the Chickenpox vaccine and has not contracted the disease. However, there are still some adults who never had Chickenpox and may be susceptible to infection during pregnancy.
Chickenpox tends to manifest as a more severe infection in adults compared to children, often involving respiratory complications. Additionally, infection during the early stages of pregnancy can lead to congenital syndromes in the fetus. Since the Chickenpox vaccine cannot be given during pregnancy (as it is a live-attenuated virus vaccine), I recommend that all women and men who are unsure whether they have had Chickenpox or received two doses of the vaccine undergo an antibody test. If they lack antibodies, it is advisable to get vaccinated (one or two doses, as needed) before planning a pregnancy. Note that women who need both the Chickenpox and Rubella vaccines can receive them in a single injection, known as the MMRV vaccine.
As I mentioned earlier, the Chickenpox vaccine is a live-attenuated virus vaccine and cannot be administered during pregnancy. Ideally, it should be given about three months before a woman becomes pregnant. Keep in mind that some women need two doses, each spaced at least one month apart. In short, the key takeaway is simple: plan ahead!
Rubella (and Measles and mumps while we’re at it)
Rubella (not to be confused with Roseola) is a mild childhood illness. However, contracting Rubella during pregnancy can negatively affect the fetus and lead to serious congenital syndromes. Therefore, all women planning to become pregnant should ensure they are vaccinated against Rubella, as the vaccine is a live-attenuated virus and cannot be administered during pregnancy. Once again, this emphasizes the importance of planning a pregnancy in advance.
When is a woman considered fully vaccinated against Rubella?
A woman who has vaccine records showing two doses of Rubella, given after the age of one, with the doses spaced at least four weeks apart, is considered vaccinated. Additionally, a woman who has been tested for Rubella antibodies and whose results show a positive result (in my country, this is at least 31 International Units or more—check your local cut-off for positive/negative results) is also considered protected. There is no need for a third dose of Rubella, as a woman with documented proof of two doses is considered fully vaccinated.
Once again, this vaccine is a live-attenuated vaccine and cannot be administered during pregnancy, so it’s important to plan ahead.
Measles and mumps – Measles and mumps are two additional viral infections that are highly unpleasant to contract, whether during pregnancy or at any time. I mention them here because the Rubella vaccine is typically given in combination with the vaccines for these two infections, known as the MMR vaccine (Measles, Mumps, and Rubella). As I mentioned earlier, the MMR vaccine is a live-attenuated virus vaccine and should be administered at least three months before becoming pregnant.
Influenza vaccine during pregnancy
There’s no need to discuss the general importance of the Influenza vaccine or its specific importance during pregnancy. However, it’s important to note that pregnancy is a known risk factor for complications from Influenza, and all pregnant women are advised to receive the flu vaccine during the flu season. Keep in mind that newborns cannot receive the flu vaccine during their first six months. By ensuring that the mother and other family members are vaccinated, the risk of Influenza spreading within the household is reduced, providing the child with added protection against this unpleasant illness. More information of Influenza vaccine can be found here.
What happens when a woman isn’t able to get vaccinated before or during pregnancy?
Keep in mind that the postpartum period (the first 6 weeks) is also an ideal time to catch up on vaccines, particularly if another pregnancy is being planned.
Pregnancy is a time when many factors are beyond our control. However, it’s worth taking the time to plan for the few factors we can manage, particularly when it comes to protecting both the mother and the baby through vaccinations.
If you’d like to read more about prevention of other diseases, that do not have vaccines, during pregnancy, I suggest you read the post about prevention of congenital Cytomegalovirus (CMV) which is super important! Aswell as, the one about prevention of another important infectious disease – Toxoplasma.
Good luck!
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