Formulae to evaluate the effect of inter-assay analytical imprecision (expressed as the coefficient of variation) in maternal serum screening for Down's syndrome have been developed. Experimentally determined imprecision in Down's syndrome risk (based on maternal serum alpha-fetoprotein, unconjugated oestriol and human chorionic gonadotrophin) was found to be consistent with predicted values. Imprecision in the measurement of analytes becomes amplified when risk is calculated using the values of these analytes. A large separation between the means and small standard deviations for normal and affected pregnancies are the characteristics of the tests most useful in screening, but these attributes also result in the most imprecision in risk. In addition, the relative imprecision associated with Down's syndrome risk is not the same for all women screened. Combining tests for multivariate analyses results in a complex compounding of the errors. The need for strict quality control and test reproducibility is emphasized. The effect of analytical imprecision should be of particular concern to laboratories that provide screening for women of advanced maternal age.

To determine the effect of routine repeat testing in serum screening for Down's syndrome, we compared estimates of the detection and false-positive rates. Five serum markers were measured--alpha-fetoprotein (AFP), unconjugated oestriol (uE3), human chorionic gonadotrophin (hCG), and its two subunits, free alpha and free beta-hCG. First and repeat test marker levels were available from 142 women whose samples had been routinely collected and stored in an antenatal serum bank. Different repeat testing policies were compared for various combinations of the markers. If all women had repeat tests using the four markers AFP, uE3, and free alpha and free beta-hCG, the detection rate for a 5 per cent false-positive rate was 69 per cent compared with 65 per cent if no women were repeated. Policies of repeating selected women gave similar results. The small gain in screening performance with repeat testing performed routinely is not worthwhile. If a woman does happen to have a repeat test, her risk estimate should, however, be based on both results, not just the second.

The aim of this study was to evaluate the additional value of dimeric inhibin-A serum concentration in second trimester multiple-marker screening tests for pregnancies affected by Down's syndrome. We anticipated that second trimester maternal serum dimeric inhibin-A concentrations would be altered in pregnancies complicated by fetal Down's syndrome and that dimeric inhibin-A would perform better than one of the three substances analysed in the multiple-marker screening test currently in use. A total of 1156 serum samples were screened for dimeric inhibin-A in parallel with the routine classic triple test screening programme performed on a random obstetric population. Classic triple test performance was compared with detection rates obtained after substitution of unconjugated oestriol by inhibin-A and with the performance of inhibin-A and alpha-fetoprotein alone. Absolute dimeric inhibin-A maternal serum concentrations of Down's syndrome pregnancies were indeed significantly higher than those of normal pregnancies in our screened population. The performance of dimeric inhibin-A in combination with the multiple-marker screening test, however, is limited because of its strong correlation with intact human chorionic gonadotrophin.

The data of 89 girls aged 4 months to 12 years, with synechia labiorum minorum, diagnosed for the first time in 1991 at the Outpatient Department of Pediatric and Adolescent Gynecology at the University Ob. & Gyn. Hospital in Sofia were analyzed (age distribution, type of synechia, kind of treatment and the effects). The same girls were followed up during the next two years (healing, adverse reactions, reappearance). According to the treatment the girls were divided in two main groups. The first group (72 girls) were treated with blunt dissection of synechia under local anesthesia (two drops anesthetic jelly), followed by two weeks treatment with non-hormonal ointment. The second group, due to old, solid synechiae, the girls were treated only with oestriol ointment. Statistically there is no significant difference in the number of reappearances between the two groups. There were no cases of scars, narrows and adverse reactions. There are differences in the duration of the treatment and in it's costs. In the first group the duration was two weeks and the costs were several times lower than in the second group which duration is 4-8-12 weeks.

To investigate whether statistical parameters used in Down syndrome screening between 15 and 22 weeks of pregnancy can be used at 14 weeks, we assayed alpha-fetoprotein (AFP), unconjugated oestriol (uE3), total human chorionic gonadotrophin (hCG), free alpha-hCG, free beta-hCG, and inhibin-A in 16 pregnancies with Down syndrome in the 14th week of pregnancy and expressed values in multiples of the normal median. The median and standard deviation values for these 16 pregnancies were not materially different from those published for 15-22 weeks. It is reasonable, therefore, to offer Down syndrome screening using these markers starting at 14 completed weeks of pregnancy instead of 15 weeks. It needs to be recognized, however, that serum AFP measurement for neural tube defect screening is less effective at this time than between 16 and 18 weeks of pregnancy.