Human placental lactogen is a first-trimester maternal serum marker of Down syndrome

Background Human placental lactogen (hPL) is synthesised by the placenta and found in maternal serum. We analysed the potential of hPL as a first-trimester maternal serum-screening marker for fetal Down syndrome (DS). Materials and Methods hPL was quantified by ELISA in 47 DS pregnancies and 136 controls in gestational weeks 8-13. Distributions of log multiples of the median (MoMs) were established. The quantity of hPL in DS screening was estimated using Monte Carlo simulation methods. Results The mean log 10 MoM hPL was -0.1995 (SD: 0.1993) in affected and 0.0026 (SD: 0.2129) in control pregnancies. This corresponds to a MoM of 0.63 in DS pregnancies. hPL correlated significantly with log10 MoM values of hCG (r = 0.320) and PAPP-A (r = 0.590) in controls, but not with hCGP (r = 0.228) or PAPP-A (r = 0.090) in DS pregnancies. The inclusion of hPL in the double test (PAPP-A + hCGP) increased the detection rate from 67 to 75% for a false-positive rate of 5%. Conclusion hPL is a DS screening marker that is applicable at weeks 9-13 and could be included in multiple marker first-trimester screening for DS. Copyright (C) 2007 John Wiley & Sons, Ltd.