Maternal serum screening for Down's syndrome in early pregnancy.

Abstract

The possibility of improving the effectiveness of antenatal screening for Down's syndrome by measuring human chorionic gonadotrophin concen- IntroductionDown's syndrome is the most common congenital cause of severe mental retardation, with an incidence at birth of about 1-3 per 1000. The current method of antenatal screening is to select women for a diagnostic amniocentesis on the basis of advanced age. Age is, however, a poor basis for screening and has had little impact on the incidence at birth. With age as a basis for screening only about 30% of all Down's syndrome pregnancies can be detected by carrying out amniocentesis on the 5% of women most at risk-that is, those aged 36 years or greater-though in practice fewer than 15% of affected pregnancies are detected because fewer than half of these older women actually have amniocentesis.' Additional antenatal screening tests such as maternal serum measurements of c fetoprotein and unconjugated oestriol can increase the rate of detection to about 45% if the 5% of pregnant

Temporal changes in maternal serum biochemical markers of trisomy 21 across the first and second trimester of pregnancy

“…The principle of multiple marker risk assessment in screening for trisomy 21 was established by Wald and co-workers in 1988 8 and the statistical methodology has been explained in detail by Reynolds and Penney?…”

eHealth Management Platform for Screening and Prediction of Down’s Syndrome in the Republic of Panama

“…This is the first marker that will be used in the platform with the method proposed by Cuckle et al [6] [22] [30]. Currents software vendors use this risk estimation method.…”

Invasive or non-invasive prenatal genetic diagnosis?

“…As a result, in the 1980s amniocentesis was offered to women at higher risk of trisomy 21 based on maternal age alone, if there was an increased risk due to prior complications or pre-existing conditions (i.e., chromosomal alterations in the parents or in prior offspring), or because of prenatal detection of fetal malformations or other abnormal ultrasound findings. The initial policies led to an offering of invasive prenatal diagnosis to 5% of all pregnant women (positive screen rate), with a 40% detection rate for trisomy 21.With the advent of biochemical screening tests using maternal serum in the second trimester, the "triple" and "quadruple screen", the detection rate of trisomy 21 increased to 60% [28]. Meanwhile, with advancements in ultrasound, numerous reports were published that identified sonographic "markers" for trisomy 21, leading to additional screening with a "genetic ultrasound" in the second trimester [1].…”

“…With the advent of biochemical screening tests using maternal serum in the second trimester, the "triple" and "quadruple screen", the detection rate of trisomy 21 increased to 60% [28]. Meanwhile, with advancements in ultrasound, numerous reports were published that identified sonographic "markers" for trisomy 21, leading to additional screening with a "genetic ultrasound" in the second trimester [1].…”