In a prospective study of screening of maternal serum levels of alpha-1-fetoprotein (MS AFP) and trofoblast-specific beta-1-glycoprotein (MS SP1) were examined in samples from pregnant women between the 16th and 18th week of pregnancy. We detected 8 fetuses with chromosomal aberation, 8 fetuses with neural tube defects and 10 fetuses with inborn cardial defects. Our study confirms higher MS SP1 levels in women with fetuses with chromosomal aberation, while MS AFP's tendency is to decrease. When combining MS SP1 + MS AFP + age of mother (over 35), 75% of fetuses with chromosomal aberation were detected. In women with neural tube defect 75% fetuses were detected by MS AFP + MS SP1 combination.