Factors during pregnancy and at birth, often interrelated,
may increase or contribute to the chances that a baby is born with or will
develop
cerebral palsy (CP). It is estimated that about 80 out
of 100 children with CP had a disruption in the normal development of parts of
their brain during fetal growth.1 The exact cause of
these disruptions is not known.
Birth trauma, in which a baby can
be deprived of oxygen or sustain a brain injury, is a rare cause of CP. The
exact cause-and-effect relationship between cerebral palsy and a difficult
birth is often unknown. Sometimes a baby has an existing brain injury sustained
during fetal growth that makes birth more difficult because of irregular
postures or other problems. Often it is impossible to determine whether the
brain injury or abnormality that results in CP occurred during fetal growth, a
problematic birth, or a combination of factors.
There are several
possible causes of CP during pregnancy or birth.
Genetic disorders
Babies born with certain
genetic disorders or blood-clotting problems have an
increased risk of cerebral palsy. Babies born to teen mothers or to mothers
older than age 35 also have a higher risk for CP.
Exposure of the mother to harmful substances during pregnancy
Examples of harmful substances include radiation or
certain medicines, such as thyroid hormone or estrogen. These and other
substances may interfere with normal fetal development. A woman who drinks
alcohol or uses illegal drugs during her pregnancy increases the chance that
her baby will develop cerebral palsy.
Infections and health problems in the mother during pregnancy or birth
Infections such as
rubella,
cytomegalovirus infection (CMV), and
toxoplasmosis in the mother, especially in the first
few months of pregnancy, have been linked to the development of cerebral palsy.
Certain infections (such as
strep infections) of the
uterus or the vagina may pass to the baby during
delivery.
Other health problems in the mother during pregnancy, such as bleeding in
the mother's uterus, having large amounts of protein in the urine
(proteinuria), or having high sugar levels in the mother's blood are all
examples of other problems that may be linked to a fetus developing CP.
Having a prolonged or difficult birth
A baby who has
a prolonged or difficult birth may be deprived of oxygen, nutrients, or blood
for a long enough period to sustain brain injury. For example, delivery of the
placenta (afterbirth) before the baby can result in a baby losing the blood or
oxygen supply from the mother too soon, which can result in CP.
Guidelines from the American College of Obstetricians and Gynecologists
and the American Academy of Pediatrics help doctors find out whether a problem
that happened during birth is serious enough to cause brain injury that may
result in CP.