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Some
vaccine-preventable infections can cause more severe illness
in pregnant than in non-pregnant women or cause serious damage
to the fetus. In an ideal world, all women of
child-bearing age would receive all recommended vaccines
before becoming pregnant in order to keep themselves and
their unborn children healthy. During pregnancy:
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Rubella
(German measles) can cause heart defects, cataracts, mental
retardation or deafness in the infant.
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Tetanus (lockjaw) can
cause an often-fatal illness in unvaccinated mothers and
newborn infants.
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Influenza has been shown to cause more
severe illness in pregnant than in non-pregnant women and often
leads to pneumonia, hospitalization and, rarely, death.
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Varicella (chickenpox) can cause severe pneumonia in
pregnant women and has caused birth defects in fetuses.
In addition to the direct benefit of preventing birth
defects in the fetus and illness in the pregnant woman,
there are other reasons why being up-to-date on vaccines is
important, especially during pregnancy.
Vaccination protects againts infection with bacteria or viruses by
stimulating the body’s immune system to produce antibodies,
or blood proteins, that in many cases are
protective. A newborn baby’s immune system is not mature or
developed enough to produce these antibodies in the first
few weeks to months of life. Antibodies from the mother are
transferred to the fetus while still in the womb. Examples
of this mother’s gift of protection include tetanus,
measles, rubella, and most likely pertussis or whooping
cough.
Many experts believe some infections are less
common in newborn infants because they have antibodies
from their mothers that prevent these infections. The
opposite also is likely to be true. Some infections can be
more severe in very young infants because their mothers have
not passed antibodies to them in the womb (because mothers
have not developed antibodies).
Unfortunately, these
antibodies transferred from mother to infant are not
permanent and gradually are lost as the infant ages. As this
happens, the infant’s immune system also is developing so
that they can produce antibodies after vaccination. So,
vaccinating women of child-bearing age either before or
during pregnancy also may protect their newborn infants
from severe illness or death from some infections.
There is no evidence that vaccination in
pregnancy is harmful to either mother or fetus. The Advisory
Committee on Immunization Practices (ACIP) has stated that
concerns that vaccinating pregnant women will affect the
developing fetus are theoretical. In fact, vaccines have been given to thousands of
pregnant women without any serious side effects in either
mother or fetus. This is especially true when vaccines are
given in the second and third trimester of pregnancy (after week 13) because by this point most body organs and systems in the fetus have developed.
Many vaccines contain inactivated (killed) viruses
and bacteria or toxoids, and there is no evidence that these
pose any risk in pregnancy. There are more concerns that vaccines that contain
live attenuated agents—such as measles, mumps, rubella (MMR);
varicella;
live attenuated influenza vaccine (LAIV)—may be harmful.
As a precaution, it is advised that women do not become
pregnant for 28 days after receiving these vaccines, even
though there has been no evidence that the fetus is damaged as a
result of these vaccines.
The Centers for Diseases Control and Prevention (CDC) have
published
recommendations for immunizing pregnant women.
These guidelines list vaccines that are recommended for all
women, recommended for women in special medical
circumstances and vaccines not recommended in pregnancy.
Breastfeeding is not a contraindication to vaccination. On
the contrary, antibodies against vaccine preventable
diseases have been demonstrated in breastmilk collected from
women vaccinated during and after pregnancy. These
antibodies may have a role in protecting infants from
acquiring diseases in the first few months of life, and
research in this area is progressing. Although virus has
occasionally been isolated from breastmilk after
administration of live, attenuated vaccines, there have been
no documented cases of clinical disease in the infants.
Vaccination in pregnancy is an important intervention to
prevent illness in mothers and to potentially prevent or
lessen the severity of illness in infants during the first
weeks to months of life. Examples of vaccines for use in
pregnancy that are being studied by investigators associated
with The Center for Vaccine Awareness and Research and Baylor
College of Medicine include:
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Pertussis (whooping cough)
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Respiratory syncytial virus (RSV), a virus that causes severe
lung inflammation and pneumonia in young infants
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Influenza
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Group B streptococcus , a bacterium that causes
bloodstream infection and meningitis in infants less than
4 months of age
To learn more about vaccines and
pregnancy, visit the CDC's
Guidelines for Vaccinating Pregnant Women.
 
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