13. Hydrocephalus
Hydrocephalus causes an enlargement of
the fetus’s head. It occurs in about 1 in 2000 babies and is
responsible for about 12% of all severe fetal malformations found at
birth.
The organization and development of the
baby’s brain and central nervous system begin early. Cerebral spinal
fluid circulates around the brain and spinal cord; fluid must be able
to flow without restriction. If openings are blocked and flow is
restricted, it can cause hydrocephalus (sometimes called water on the brain). Fluid accumulates, and the baby’s head becomes enlarged.
Hydrocephalus is only a symptom, and it
can have several causes. Once hydrocephalus is diagnosed, a cause is
sought; these include spina bifida, meningomyelocele and omphalocele.
Sometimes intrauterine therapy—therapy performed while the fetus is
still in the uterus—is possible. See the discussion in the following
section.
14. Prenatal Treatment of the Fetus
In this discussion, “prenatal
treatment” refers to treatment of the baby, not treatment of a pregnant
woman. Treatment of a fetus in utero has proved to be a valuable tool
in saving the lives of some babies.
15. Cordocentesis
The earliest form of in-utero
treatment involved blood transfusions to fetuses with a
life-threatening form of anemia. We now have more refined
blood-transfusion techniques. Cordocentesis is a transfusion procedure
by which blood is introduced directly into the fetal bloodstream
through the umbilical cord.
The greatest use of medication in utero
is to hasten development of fetal lungs. If you’re at high risk for a
preterm birth, your healthcare provider may recommend this treatment to
ensure that your baby’s lungs are adequately developed before birth. If
a baby is born before its lungs are mature, it can develop
respiratory-distress syndrome.
If your healthcare provider believes you
are at risk of delivering your baby before 34 weeks gestation, he or
she may prescribe corticosteroid injections. This medication passes
from your bloodstream into the fetus’s bloodstream, reducing the risk
of infant death or the risk of complications, such as breathing
problems. It appears to be safe for both mother and fetus.
A less common problem that may be treated
before birth with medication is a heart-rhythm disturbance. Medication
is usually given to the mother to treat her baby. In some cases,
healthcare providers deliver medication directly to the fetus via
cordocentesis.
Other problems cordocentesis is
used for include inherited inborn errors of body chemistry. Treatment
with medication given to the mother has been very successful.
16. Fetal Surgery
Fetal surgery can treat various
problems while a baby is still growing inside the mother. Open surgery
or closed-uterus surgery may be performed.
Most surgeries, whether open or
closed-uterus, are not performed until at least 28 weeks of pregnancy.
Surgeries treat a variety of problems, including urinary-tract
blockages, tumors and fluid in the lungs.
With open surgery, the surgeon
makes a Cesareanlike incision in the mother’s abdomen, partially
removes the fetus, performs surgery, then returns the fetus to the
uterus. Open surgery carries risks for mother and baby. One problem
with open surgery is it may stimulate uterine contractions, which can
lead to premature birth. The surgery exposes the mother to all the
risks of surgery, including anesthesia problems and infections. After
open surgery, the mother must have a Cesarean delivery when it is time
to deliver the baby.
Closed-uterus procedures
are more common than open surgeries. With this surgery, miniature
cameras guide a needle-thin fiberoptic instrument into the fetus’s body
while the fetus remains inside the uterus. The most successful
closed-uterus surgeries are associated with the opening of
urinary-tract blockages.
