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Some vaccine-preventable
infections can cause more severe illness in pregnant
than in non-pregnant women and/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:
·
Rubella (German measles) can cause heart defects, cataracts, mental
retardation or deafness in the infant.
·
Tetanus (lockjaw) can cause an often-fatal illness in unvaccinated
mothers and newborn infants.
·
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.
·
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 against 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 antibodies to tetanus,
measles, rubella, and most likely pertussis or whooping cough.
Some
infections are less common in newborn infants because they have
antibodies from their mothers that prevent these infections. The
opposite also is 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, some vaccines (e.g.,
tetanus toxoid vaccine and influenza vaccine) have been given to
millions 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 fetal body organs and systems are fully
developed.
Many vaccines contain inactivated (killed) viruses, 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 live-attenuated
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.
. 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 of
these mothers.
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:
-
Pertussis (whooping cough)
-
Respiratory syncytial virus (RSV), a virus that causes severe
lung inflammation and pneumonia in young infants
-
Influenza
-
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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