[The experience of the genetic laboratory in Varna on maternal serum screening for a six year period].

The aim of the presentation is to report the results of the Genetic laboratory in University hospital "St. Marina" Varna on second (15-19 gw) and first trimester (12-14 gw) maternal serum screening for common chromosome disorders, for the period 2005-2010. The test was performed on 10741 pregnant women from 8 regions of North-Eastern Bulgaria: 9743 women were screened in the second trimester (8251 at the age < 36 and 1492 at the age > 36) and 998 women - in the first trimester (827 at the age < 36 and 171 at the age > 36). The fluorimetric dual method was based on biochemical markers; software calculated risk as function of precise gestational age, maternal weight and age. The most common strategy was to combine the risk as determined from first and second trimester screening test in a sequential manner. High risk for a chromosome disorder (a risk above 1:250) was found by second trimester screening in 784 (8,04%): 488 (5,91%) <36 and 296 (19,83%) >36. The most recent first trimester screen test, which have been involved in the laboratory since April 2010 detected 7 (0,84%) and 23 (13,45%) women respectively to the age groups with increased risk for a chromosome disease. Additional ultrasonographic scan confirmed the biochemical risk for a serious Neural Tube/Abdomainal Wall defects in 5 out of 32 fetuses with increased risk for these defects; other 3 fetuses were detected to be involuntary miscarried as "missed abortion", 1 triploidy included. We comment on the sensitivity, limitations and the stepwise sequential testing way of achieving a high performance of screening for chromosome diseases based on preliminary information to pregnant women on different options for a contemporary approach for genetic prevention.