Serum PAPP‐A measurements in first‐trimester screening for Down syndrome

Abstract

Serum PAPP-A measurements taken from 254 women in the first trimester are reported. Eleven chromosomal abnormalities were detected. The mean serum PAPP-A levels in cases of Down syndrome were 0.44 MOM at 9 weeks gestation, 0.15 MOM at 10 weeks, and 0.29 MOM at 11 weeks. The PAPP-A level at 10 weeks was below those of pregnancies which aborted spontaneously. At 11 weeks, the pregnancies with Down syndrome recorded the lowest PAPP-A levels at that gestation. On this small sample, offering chorionic villus sampling to women with singleton pregnancies and a PAPP-A level below 0.3 MOM (approximately 6.5 per cent of this at-risk group) would have detected all the Down syndrome fetuses at 10 weeks and 50 per cent at 11 weeks without selecting those cases destined to abort. This suggests that serum PAPP-A should continue to be investigated as a potential first-trimester screening test for Down syndrome.

Efficiency of Ultrasound and Biochemical Markers for Down’s Syndrome Risk Screening

“…This biochemical marker has been suggested as the single most effective in first-trimester screening [21] but, at the time of our study, this marker could not be measured by means of a reproducible automated method.…”

FIRST-TRIMESTER BIOCHEMICAL SCREENING FOR DOWN SYNDROME WITH THE USE OF PAPP-A, AFP, AND β-hCG

“…PAPP-A is detectable in maternal serum by about the 30th day of pregnancy and MS-PAPP-A levels increase exponentially until term, then gradually decrease and are undetectable by the sixth postpartum week (Sinosich, 1985). MS-PAPP-A concentrations are significantly reduced in the presence of a fetus with DS, suggesting this as a sensitive marker during the first trimester (Brambati et al, 1991(Brambati et al, , 1994Cuckle and Lilford, 1992;Wald et al, 1992;Hurley et al, 1993;Bersinger et al, 1994;Macintosh et al, 1994;El Farra and Grudzinskas, 1995).…”

First‐trimester screening and its impact on uptake of diagnostic testing

“…Hurley et al demonstrated that a decreased level of PAPP-A was associated with trisomy 21 and that these low levels could be detected as early as the first trimester. From these results, they concluded that using a cut off of 0.3 multiples of the median for PAPP-A, pregnancies at an increased risk for trisomy 21 could be identified (Hurley PA et al, 1993). Use of PAPP-A in conjunction with maternal age was also studied as a first trimester screening technique for trisomy 21 (Brambati B, Macintosh MC, Teisner B, Maguiness S, Schrimanker K, Lanzani A et al, 1993).…”

“…In the early 1990s the maternal analyte PAPP-A was studied to determine its usefulness as a screening tool. These studies wanted to understand if there was a correlation between the amount of PAPP-A in maternal blood and fetal aneuploidy or demise (Hurley PA, Ward RH, Teisner B, Iles RK, Lucas M, Grudzinskas JG., 1993). Hurley et al demonstrated that a decreased level of PAPP-A was associated with trisomy 21 and that these low levels could be detected as early as the first trimester.…”