Absence of need for amniocentesis in patients with elevated levels of maternal serum alpha-fetoprotein and normal ultrasonographic examinations

Article Abstract:

The blood of pregnant woman is routinely tested for the presence of alpha-fetoproteins, proteins produced by the fetus that are associated with various birth defects, particularly those involving the developing nervous system (neural tube), the digestive system and the abdominal wall. Expectant mothers also receive ultrasonic (US) examinations to detect fetal defects. A probe is placed on the abdomen which transmits high-energy sound and then measures its reflection to produce an accurate image of the fetus. In the presence of elevated levels of maternal blood alpha-fetoproteins and the absence of fetal abnormalities detectable by ultrasound, amniocentesis is usually performed. In this procedure, a needle is placed through the mother's abdominal wall into the uterus, where fluids inside the amniotic sac are withdrawn for a more sensitive analysis of the presence of alpha-fetoproteins. Normal levels of alpha-fetoprotein in the amniotic fluid, even in the presence of elevated levels in the mother's blood, are highly indicative of a fetus that is free of neural tube and abdominal wall defects. Amniocentesis, being an invasive procedure, is associated with a low but definite risk of lethal injury to the fetus, and it would therefore be useful to have a reliable diagnostic method that posed no risk. This study examines the ability to detect severe fetal abnormalities by means of ultrasound and maternal blood sampling only. From a large group pregnant woman, 51 cases of fetal abnormalities involving either the neural tube or abdominal body wall were reviewed; four different classes of abnormalities were examined. All cases of fetal abnormalities were successfully identified by maternal screening and ultrasound examination. The risk of missing a diagnosis of fetal abnormality was seen to be lower than the risk of abortion following amniocentesis. Some patients in consultation with their physicians may decide to rely on ultrasound data for the confirmation of abnormalities in the presence of elevated maternal levels of alpha-fetoproteins, rather than risk a chance of fetal death due to amniocentesis. (Consumer Summary produced by Reliance Medical Information, Inc.)

Management, Usage, Birth defects, Amniocentesis, Alpha fetoproteins, Prenatal ultrasonography, Ultrasonics in obstetrics

---

Humeral shortening in second-trimester fetuses with Down syndrome

Article Abstract:

Women over 35 years old are at increased risk of having children with Down syndrome, a congenital condition of moderate to severe mental retardation and physiologic abnormalities. It is standard medical practice to offer amniocentesis (sampling of the amniotic fluid, in which the fetus floats, for abnormal chromosomes) to women of that age, but other, less invasive, tests may also be of diagnostic use. Several anatomic features are characteristic of Down syndrome, including a shortened femur (thigh bone), shortened humerus (bone of the upper arm), and thickened nuchal fold (a thickening at the nape of the neck). To learn more about the value of ultrasound for diagnosing Down syndrome in fetuses between 14 and 20 weeks' gestational age, a study was carried out of more than 3,100 patients who also underwent amniocentesis. Several fetal measurements, including humeral and femoral lengths, nuchal fold size, and biparietal diameter (BPD; a measure of skull diameter) were made. Twenty-four fetuses with Down syndrome were identified by amniocentesis; measurements were carried out using the sonograms (ultrasound records) from these fetuses and from 400 fetuses with normal chromosome counts (the control group). Eighteen of the 24 Down syndrome fetuses had abnormally short humeral lengths and 12 had abnormally large nuchal folds. Ten Down syndrome fetuses had an abnormally short femoral length. When nuchal fold measurements were combined with humeral length measurements, the ultrasound results correctly identified 18 of the fetuses (75 percent sensitivity). The positive predictive value of this measurement (the probability that a fetus identified as Down syndrome on ultrasound actually has the disorder) for a 35-year-old woman was 4.6 percent. A discussion is presented of the ability of ultrasound to diagnose Down syndrome. Although this approach cannot be considered an absolute screening test, the fact that more women undergo ultrasound than amniocentesis provides the opportunity for analysis of their sonograms to identify anatomical abnormalities consistent with Down syndrome. (Consumer Summary produced by Reliance Medical Information, Inc.)

Fetus, Physiological aspects, Down syndrome, Doppler ultrasonography, Femur, Humerus

---

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: Ultrasound detection of fetal aneuploidy in patients with elevated maternal serum alpha-fetoprotein. Fetal pyelectasis: a possible association with Down's syndrome
• Abstracts: Gram stain results from amniocentesis in patients with preterm premature rupture of membranes - comparison of maternal and fetal characteristics
• Abstracts: Autoantibodies in patients with juvenile chronic arthritis and their immediate family relatives. Pulse methylprednisolone therapy in rheumatoid arthritis: unproved therapy, unjustified therapy, or effective adjunctive treatment?
• Abstracts: Maintenance treatment with recombinant interferon alfa-2b in patients with multiple myeloma responding to conventional induction chemotherapy

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