Anemia of Prematurity - Portal Neonatal

AFP concentration in the maternal serum is usually lower than 500 ng/mL. Determining precise
gestational age is essential because fetal AFP levels are age specific and can peak in a normal fetus
at 12-15 weeks of gestation. For example, at 20 weeks' gestation, a maternal serum AFP
concentration higher than 1,000 ng/mL would be indicative of an open NTD. The measurement of
maternal serum AFP levels is more than 75% accurate in detecting an open NTD at more than 15
weeks of gestation. In patients in whom a question persists, amniotic AFP can be obtained. It is a
significantly more accurate test, especially at 15-20 weeks' gestation, and detects approximately 98%
of all open NTDs, although this method is not the preferred screening test. Amniotic fluid
acetylcholinesterase levels add an increased degree of resolution.
Detection of an NTD with fetal ultrasound in the hands of a skilled ultrasonographer usually is 98%
specific. False-positive findings can result from multiple pregnancies or inaccurate fetal dating.
However, closed NTDs also can sometimes remain undetected, especially in cases of skin-covered
lipomyelomeningoceles and meningoceles, in which the AFP also may be normal. These closed
NTDs comprise about 10% or more of total NTDs discovered. A skilled ultrasonographer can detect
these lesions with almost 95% sensitivity.
A partial list of the fetal anomalies that are associated with an elevated AFP is as follows:
• Anencephaly
• Spina bifida cystica
• Encephalocele (leaking)
• Conjoined twins
• Omphalocele
• Turner syndrome
• Gastroschisis
• Extrophy of the cloaca
• Oligohydramniosis
• Sacrococcygeal teratoma
• Polycystic kidneys
• Fetal death
• Urinary tract obstruction
If the parents decide not to terminate a pregnancy in which the fetus is affected with an NTD,
extensive counseling takes place. Parents are educated on optimal prenatal care and expectations
once a child is born. If diagnosed early enough, a discussion of fetal surgery is warranted. Currently,
this option is available at only 2 major centers: Vanderbilt Medical Center and University of
Pennsylvania. Although this approach has not been proven scientifically advantageous, preliminary
evidence suggests that this experimental approach has promise in decreasing resultant neurologic
problems in the neonate. Long-term outcome data are currently lacking.
If conventional delivery is chosen, the study by Shurtleff and his colleagues is important to note.
Infants with NTD who were exposed to labor and vaginal delivery were more than 2 times more likely
to have severe paralysis or motor deterioration than those delivered by cesarean section without
labor. Although this remains a controversial point, most centers such as that of the author recommend
a cesarean section prior to labor in mothers carrying a fetus with a myelomeningocele.
EVALUATION AND TREATMENT: MEDICAL AND
SURGICAL
Neurologic lesions
Section 8 of 11
The myelomeningocele is a saccular protrusion containing a neural placode bathed in CSF (see
Image 1). The surface of the sac is covered by arachnoid but no dura or skin. The sac appears
velvety red or yellow with thin fragile vessels imbedded in the arachnoid. The nerve roots pass