by Playfuls Staff |
30th January 2007
The first researchers to use magnetic resonance imaging
(MRI) to study the brains of a large group of babies soon after birth found a
small amount of bleeding in and around the brains of one in four babies [more] who
were delivered vaginally. The study appears in the February issue of Radiology.
"Small bleeds in and around the brain are very common
in infants who are born vaginally," said John H. Gilmore, M.D., professor
of psychiatry and Vice-Chair for Research and Scientific Affairs at the
University of North Carolina School of Medicine in Chapel
Hill. "It seems that a normal vaginal birth can cause these
small bleeds."
For the study, 88 asymptomatic infants, equally divided
between male and female, underwent MRI between the ages of one and five weeks.
Sixty-five had been delivered vaginally and 23 had been delivered by cesarean
section. MR images showed that 17 (26 percent) of the babies who had been
delivered vaginally had intracranial hemorrhages (ICH), or small bleeds in and
around the brain. Seven infants had two or more types of ICH. Prior studies
have shown a smaller incidence—approximately 10 percent—of intracranial
hemorrhage associated with vaginal birth.
While ICH was significantly associated with vaginal birth,
it was not dependent on prolonged duration of labor or on traumatic or assisted
vaginal birth.
In a newborn, the bones of the skull have not fused
together, so the bones of the skull can shift and frequently overlap each other
during vaginal delivery, to allow the baby's head to fit through the birth
canal. This shifting can compress the brain or cause blood vessels to tear,
which causes bleeding.
Most of the bleeds identified were very small subdural
hematomas—bleeding between the brain and the thick membrane that covers the
brain below the skull—and a majority of them were located in the lower, back
part of the brain over the occipital lobe or the cerebellum, which is below the
occipital lobe.
Typically, small bleeds resolve over time without causing
problems, though larger ones may cause problems later in the child's life,
including seizures, subtle learning problems or problems with motor
development.
Further studies must be done to measure the long-term
effects of ICH in infants, but Dr. Gilmore noted that expectant parents should
not rule out vaginal delivery because of these findings.
