Unless the potential
risks outweigh the clear benefits, live vaccines should not be administered
during pregnancy because there are theoretical concerns for fetal harm. But
till date there is no evidence of teratogenic effect of any of the live
vaccines- measles, mumps, rubella, varicella or polio. Similarly in the case of
live-attenuated vaccines, the risk of insufficient control of replication of
the vaccine strain is only theoretical which has not been proven yet.
regarding immunization in pregnancy is a mercury-containing compound
(thimerosal), which is used as a preservative in vaccines. Studies have shown
that the breakdown product of thimerosal- ethyl mercury does not accumulate and
does not cause harm to the fetal brain like methyl mercury. Also there is no
increase in neurodevelopmental disorders due to exposure to
thimerosal-containing vaccines. Now a days all vaccines, except the Japanese
encephalitis vaccine have a thimerosal-free alternative. But unavailability of a thimerosal-free vaccine
should not preclude administration of the vaccine.
Vaccination in pregnancy
- Ideally women should
be vaccinated for Hepatitis B prior to pregnancy. But due to some reasons if
they are not immunized for Hepatitis B and are at a high risk for Hepatitis B
and have tested negative for the virus can receive this vaccine. Vaccination
protects mother and baby against hepatitis B infection both before and after
- This vaccine can be
administered only after 14weeks of pregnancy. In case of serious medical
condition, which can lead to flu-related complications, the vaccine can be
given at any stage during pregnancy. Maternal vaccination
during pregnancy has the potential to decrease the probability of neonatal
influenza. In 2009 when the H1N1
influenza vaccine became available, pregnant women were among the initial
target groups for immunization with this inactivated vaccine.
- This vaccine is
routinely recommended for pregnant women.
- Pregnancy is not a
contraindication for the typhoid vaccine and women who are
anticipating travel to endemic areas like Latin America, Africa and Asia should
be counseled about vaccination. Though several forms of typhoid vaccines are
available, experts recommend the use of capsular vaccines.
- The safety of this vaccine is yet to be determined. The
available data on the safety of this vaccine is very limited. Though pregnancy
is not a contraindication, women at high risk should discuss its health
implications with their gynecologists.
- Immunization with the pneumococcal vaccine during pregnancy prevents acquiring
the infection and also provides protection to young infants from these
It is safe to administer the pneumococcal polysaccharide
vaccine to women in the third trimester of pregnancy. Following vaccination it
was observed that there was an increased concentration of IgA antibodies in the
mother's breast milk. Thus immunity may be conferred to the newborn through
this route as well.
- So far there has been no adverse outcomes with
the inactivated or live-attenuated oral polio vaccines (OPV) when administered
during pregnancy. But it is better to avoid the vaccination on theoretical
grounds unless necessary. However if a pregnant woman does require immediate
protection, then the live-attenuated form of the vaccine may be considered.
Measles, Mumps, Rubella (MMR)
- Every woman should receive a shot of the MMR vaccine at least 3-months before
conceiving. This vaccine is contraindicated during pregnancy and if a woman is
non-immune to rubella then it should be given after delivery. Unintentional MMR
vaccination during pregnancy is not a reason for termination of pregnancy.
- The varicella vaccine
is recommended at least 4 months prior to conception. It is contraindicated
during pregnancy. In non-immune women it should be given in the post-partum
period. However accidental vaccination during pregnancy is not a ground for
Certain new vaccines
are being developed which can be administered during pregnancy for the maternal
and fetal well-being. These vaccines are the congenital cytomegalovirus (CMV),
vaccines against malaria, vaccine for Group B Streptococcus
(GBS) infection and vaccine for the respiratory syncytial virus (RSV).
is not a single vaccine, which is specifically approved by the FDA for use
This is primarily due to the absence of
industry-sponsored trials in pregnant subjects. Therefore future vaccine trials
must include pregnant women, especially when a particular vaccine is indicated
Women's Health. 2011;7(1):109-119