Potential prenatal predictions of Down syndrome: a statistical analysis

Article Abstract:

Down syndrome, a cause of mental retardation, is caused by inheritance of an abnormal chromosome. Pregnant women, particularly those over age 35, are frequently screened to determine if their fetuses are at risk for Down syndrome. Screening blood tests provide an initial indication of which women should most likely consider undergoing the risk of amniocentesis in order to analyze fetal chromosomes. Proposed markers for Down syndrome include low maternal blood levels of alpha-fetoprotein (AFP), levels of the hormone human chorionogonadotropin (hCG), and the ratio of fetal biparietal (skull bones) diameter to femur (thigh bone) length. Because final risk of the disorder is best determined if such analyzed indicators are mutually independent, the association of these markers with maternal age were evaluated. Maternal age did not correlate with AFP, hCG, or diameter/length ratio. Levels of hCG and AFP correlated significantly. The diameter/length ratio and hCG levels were the most promising indicators of Down syndrome. Determination of the ratio value would not incur much extra cost, as this data can be obtained from the ultrasound scans that most women undergo before amniocentesis. The ratio value combined with those for AFP and hCG are likely to be good indicators of Down syndrome, but further extension of this research is needed to verify the validity of this conclusion for the larger population. (Consumer Summary produced by Reliance Medical Information, Inc.)

Usage, Medical screening, Health screening

---

The effect of gestational age on the detection rate of Down's syndrome by maternal serum alpha-fetoprotein screening

Article Abstract:

Down's syndrome is a chromosomal abnormality that causes mental retardation, retarded growth, and abnormal facial features. Increased maternal age is one risk factor for this syndrome. Low levels of maternal serum alpha-fetoprotein (AFP), a fetal protein found in adults, have also been associated with an increased risk for Down's syndrome. These two factors together are now used in screening for Down's syndrome. Some studies have indicated that the time during pregnancy when AFP levels are measured is an important factor in whether or not screening is reliable. Data from 51 women who had been screened using AFP levels and who had Down's syndrome pregnancies were compared with findings for 3,239 randomly selected women who had been screened and who had normal pregnancies. The groups were further subdivided by gestational age at which the AFP test was performed. AFP levels at the time of screening were decreased in 25 of the 51 cases of Down's syndrome. Results showed that AFP levels were lowest in both groups when testing was performed between 16.5 and 17.5 weeks' gestation. The results suggest that AFP screening for Down's syndrome may be most effective between 16.5 and 17.5 weeks' gestation. (Consumer Summary produced by Reliance Medical Information, Inc.)

Evaluation, Physiological aspects, Genetic screening, Genetic testing, Gestational age

---

Prenatal diagnosis of diverse chromosome abnormalities in a population of patients identified by triple-marker testing as screen positive for Down syndrome

Article Abstract:

Follow-up on triple marker testing may identify chromosomal abnormalities other than Down syndrome. Triple testing measures maternal blood levels of alpha-fetoprotein, human chorionic gonadotropin, and estriol. Triple testing was carried out on 11,434 pregnant women between 15 and 22 weeks pregnant. Follow-up information was available on 74% of the women. Fourteen (5%) Down syndrome fetuses had positive triple tests. Calculations show the expected number to be 20, therefore 70% were detected. Twelve cases of other chromosomal abnormalities were found among the 468 patients who had genetic analysis. Only one was diagnosed during ultrasound imaging. Except for two cases of one type of sex chromosome abnormality, whose occurrence is known to correlate with abnormal triple testing results, the rest are believed to be serendipitous discoveries.

Methods, Gonadotropin, Gonadotropins, Estrogen, Estrogens, Chromosome abnormalities, Prenatal diagnosis

Similar abstracts:

• Abstracts: Postviral fatigue syndrome. Pseudo-Bartter's syndrome in cystic fibrosis
• Abstracts: Invasive treatment of pancreatic fluid collections with surgical and nonsurgical methods. Cholecystectomy provides long-term symptom relief in patients with acalculous gallbladders
• Abstracts: Treatment of polymyalgia rheumatica with intramuscular injections of depot methylprednisolone
• Abstracts: Preoperative percutaneous drainage of diverticular abscesses. Factors influencing the treatment of intra-abdominal abscesses
• Abstracts: Efficacy and toxicity of sodium stibogluconate for mucosal leishmaniasis. War syndromes and their evaluation: from the U.S. Civil War to the Persian Gulf War

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