Alternatively, lower levels of all of these markers are associated with Edward's syndrome.5 Studies have also shown that these quadruple markers could also be used in the prediction of small for gestational age babies.10 Studies suggest that the maternal serum AFP and unconjugated estriol are reduced on average by 2530% in pregnancies with Down's syndrome,11-13 and the levels of hCG and inhibin A are twice as high as those in normal pregnancies.14-15 Prenatal screening for specific foetal abnormalities has become a part of routine obstetrical care.16 This evidence concerns the gene AFP and trisomy 18.