Ultrasound detection of fetal aneuploidy in patients with elevated maternal serum alpha-fetoprotein

Article Abstract:

Alpha-fetoprotein is a protein that is found in the blood of adults. The amount of this protein increases during pregnancy, and abnormally high levels (twice normal levels) in the maternal blood generally indicate that the fetus may be abnormal. It has therefore become common practice to measure the amount of this protein in maternal blood samples. If large amounts of this protein are found, then the blood is tested a second time to confirm the results. If the second test yields similar results, an ultrasound is performed to look for fetal abnormalities. If the results of ultrasound imaging are normal, the patient is offered an amniocentesis (a diagnostic procedure that involves analysing the fluid inside the amniotic sac surrounding the developing fetus). However, the likelihood of detecting fetal abnormalities by amniocentesis in a patient with a normal ultrasound test is low. A recent survey reported that 60 percent of women with normal a ultrasound elect not to have amniocentesis. However, some people believe that amniocentesis should be performed, regardless of the results of the ultrasound, to determine if the fetus has an abnormal number of chromosomes (aneuploidy). The results are reported of a study designed to determine the chance of finding an abnormal number of fetal chromosomes with amniocentesis when the ultrasound findings are normal. The study included 313 pregnant women with high blood levels of alpha-fetoprotein; amniocentesis and ultrasound were performed on each woman. The amniocentesis identified four cases of chromosome abnormalities, but three of these cases were also identified with ultrasound. These results indicate that the risk of chromosome abnormalities when the results of ultrasound examination are normal is very small (0.3 percent). The risks of amniocentesis for the purpose of detecting aneuploidy are thus not warranted when ultrasound results are normal. (Consumer Summary produced by Reliance Medical Information, Inc.)

Methods, Cases, Ultrasound imaging, Measurement, Amniocentesis, Aneuploidy, Prenatal diagnosis, Alpha fetoproteins

---

Fetal pyelectasis: a possible association with Down's syndrome

Article Abstract:

Mild fullness of the kidney collection system, pyelectasis, is not an uncommon finding when the fetus is visualized by prenatal ultrasound. In most cases there are no other functional or structural abnormalities detected. However, some investigators have found that the more severe grades of pyelectasis are associated with chromosomal defects. To see if mild pyelectasis is associated with the chromosomal abnormality known as Down's syndrome, 210 fetuses with ultrasonographically detected kidney pyelectasis were studied. Seven of these fetuses were diagnosed with Down's syndrome, an abnormal number of chromosomes, ascertained either by amniocentesis or observed at birth. The kidneys of 44 fetuses diagnosed with Down's syndrome were also scanned with ultrasound. Eleven (25 percent) of the Down's syndrome infants had pyelectasis. It is concluded that the majority of fetuses with mild kidney pyelectasis have a normal number and configuration of chromosomes. When the diameter of the kidneys measures more than four millimeters (mm) during an ultrasound performed between the 16th and the 20th week of pregnancy, five mm at 20-30 weeks or seven mm at 30-40 weeks, the incidence of Down's syndrome is 3.3 percent. Although fetal kidney pyelectasis is not in itself a risk factor for Down's syndrome, it can be a useful adjunct to the other signs and symptoms highly suggestive of Down's syndrome. (Consumer Summary produced by Reliance Medical Information, Inc.)

Risk factors, Down syndrome, Prenatal ultrasonography

---

Abnormal karyotype of fetuses with omphalocele: prediction based on omphalocele contents

Article Abstract:

Omphalocele, a hernia of the abdominal contents through a hole in the intestinal wall at the umbilicus, is a rare fetal malformation. Survival is poor when multiple defects are present. Studies have shown that when the liver was not found within the omphalocele, the chromosome configuration (number or location) was usually abnormal. To develop a prognosis for fetuses with omphalocele, the chromosomes of 22 fetuses with omphaloceles were analyzed. Ultrasonographic fetal imaging, the use of high frequency sound to visualize internal structures of the fetus, was used to reveal the contents of the omphalocele. The results were compared with those from chromosomal karyotyping, a laboratory technique of identifying chromosomal abnormalities. Of the 22 fetuses, 18 had a normal karyotype and four had an abnormal karyotype. The liver was located within the omphalocele in 16 of the fetuses with a normal karyotype. The omphalocele contained only intestines in the remaining two. All of the four fetuses with abnormal karyotypes had omphaloceles that did not contain the liver. It is concluded that the absence of the liver within the omphalocele is associated with an abnormal chromosomal karyotype. An arrest in normal fetal development may explain the absence of the liver within the omphalocele. (Consumer Summary produced by Reliance Medical Information, Inc.)

Genetic screening, Genetic testing, Karyotypes, Navel, Umbilical hernia

Similar abstracts:

• Abstracts: Colon cancer in pregnancy with elevated maternal serum alpha-fetoprotein level at presentation. Prenatal diagnosis of a chest wall mass with ultrasonography and Doppler velocimetry
• Abstracts: A Phase I trial of an outpatient regimen of recombinant human interleukin-2 and alpha-2a-interferon in patients with solid tumors
• Abstracts: Perinatal outcome in triplet versus twin gestations. Uterine leiomyomas in pregnancy: a prospective study. The biophysical profile in labor
• Abstracts: The national impact of ritodrine hydrochloride for inhibition of preterm labor. Beta-adrenergic agonists for preterm labor

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.