The current trend in prenatal diagnosis is that trisomy screening is being moved to the first trimester and ultrasonographic nuchal translucency measurement is included in risk calculation. It is likely that biochemical screening in the second trimester will gradually be given up. In Eastern and Northern Finland, during the year 1999 we offered first-trimester ultrasonographic and serum screening for trisomy 21, with measurements of maternal serum PAPP-A and b-hCG. A total of 2515 pregnant women participated in the screening, yielding the detection of eight foetuses with Down's syndrome. Six affected foetuses (75%) were detected by means of first-trimester serum screening. Since we were in the phase of collecting data for the Finnish medians for PAPP-A and b-hCG, the women were not given the estimates of risk for trisomy 21. Only 1602 of the 2515 enrolled women had the combination of first-trimester ultrasonographic and serum screening performed, and in that group there were five foetuses with Down's syndrome. The combination ultrasonographic and serum approach yielded a Down's syndrome detection rate of 80% (four out of five) with a 5% false positive rate, whereas in nuchal translucency based-screening the detection rate was 60%, with a 5% false positive rate. European Journal of Human Genetics (2001) 9, 404 ± 408.

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Placental protein 14 isolated from the human placenta and its adjacent membranes, and progestagen-dependent endometrial protein (PEP) isolated from the endometrium have been described independently by two groups. We report results of the radioimmunological and immunodiffusion tests which show that the proteins are immunologically indistinguishable from each other.

Objective To analyse the effects of smoking on first trimester parameters used in prenatal screening for Down's Syndrome. Design A chart study.Setting Primary care centres and maternity clinics of the participating universities' and central hospitals.Population Three thousand and one hundred fifteen women screened by nuchal translucency measurement and 4436 women screened by maternal serum samples. Only normal singleton pregnancies were included. Methods The mean multiples of median of pregnancy associated plasma protein A (PAPP-A), free beta human chorionic gonadotrophin (h-hCG) and nuchal translucency were compared by independent samples t test after logarithmic transformation of the data between smokers and non-smokers. Main outcome measures PAPP-A and free h-hCG concentrations and nuchal translucency measurements.Results PAPP-A was significantly reduced and nuchal translucency increased if the mother smoked. The smokers were more frequently considered as being at high risk for Down's Syndrome. Conclusions Correcting PAPP-A median for smokers down by 20% might improve the accuracy of the risk evaluations given to individual women. If the association between increased nuchal translucency and smoking can be confirmed, it poses interesting questions as to the reasons for increased nuchal translucency among normal pregnancies.

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