Objective. To assess the effectiveness of antenatal screening for chromosomal abnormalities based on maternal age (≥35 years), positive ultrasound findings or a positive triple test. Materials and methods. Retrospective six-year study. The pregnant women routinely underwent established clinical and laboratory practice at the Department of Medical Genetics between 1997 and 2003. The women's case notes were examined to identify indications for karyotyping, gestation period and the outcome of karyotyping and pregnancy. Results. Invasive antenatal tests were performed on 1440 cases, 1168 (81.11%) age 35(a), 72 (5.00%) positive triple test (b), 24 (1.67%) positive ultrasound scanning (c) and 176 (12.2%) other (psychological, personal reasons, etc) (d). The overall positive predictive value was 1.67% (1.6%(a), 1.4% (b), 12.5% (c), 0.0% (d). The constructed model of logistic regression gave an odds-ratio of 8.647 for the "positive ultrasound result vs. maternal age ≥35" indication, while the odds-ratio for the triple test vs. maternal age ≥35 was 0.854. Conclusions. Amniocentesis and cytogenetic analysis of foetal karyotype should be presented as a diagnostic possibility to all women over 35 years. The application of biochemical markers was far from the expected results. If we compare results for indication positive ultrasound scanning vs. maternal age, an oddsratio of ~9 was obtained. These results demonstrate that the likelihood of obtaining positive results (i.e. the presence of chromosome alterations) from an amniocentesis having this indication is almost 9 times higher than from having an amniocentesis performed solely for advanced maternal age.

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In a previously published article (Resta et al., 2006) on Robert's syndrome in prenatal diagnosis, a case of a 36-year-old woman and her 36-year-old, nonconsanguineous husband were presented. Our findings suggest the existence of nonsense mediated decay (NMD) variability which could account for the varying severity reported in carriers of identical mutations. Furthermore, fetal cells were used to evaluate the influence of premature centromere separation (PCS) on the sister chromatid exchange (SCE) and micronucleus (MN) frequency. Given the similar variation observed in the SCE frequencies, dependent on tissue/cell type (amniotic fluid sample, chorionic villus sampling) and duration of in vitro cultures (48 hours or 72 hours), the idea was that this new piece of information could be interesting. It seems that the SCE frequency increased proportionally to the cell cycle increasing (1° < 2° < 3° … n). Obviously, our observations are too scarce to draw conclusions, but further investigation could be useful to corroborate or dispute these results, considering that the two techniques, (MN and SCE), are simple to perform and do not require expensive laboratory equipment.