Biochemical Genetics

The likelihood of fetal chromosomal anomalies can be calculated based on the serum concentration of various proteins, protein- and steroid-hormones. In addition measurement of AFP facilitates calculation of risk for fetal neural tube defects.  

Based on the outcome (statistical likelihood for a given fetal anomaly) of non-invasive prenatal screening tests, women can make a decision whether or not to have an invasive prenatal test performed. The latter gives definite results as to the karyotype of the fetus. However, these tests that include amniocentesis and chorionic villus sampling have a 0.5-2% risk for a miscarriage.