Chorionic villus sampling and amniocentesis: what are the risks in current practice?

PURPOSE OF REVIEW: Public demand for genetic counselling and prenatal diagnosis has increased during the past decade. As invasive diagnostic methods, such as chorionic villus sampling and amniocentesis, still have an important role to play in evaluating the fetus, one of the most important questions to address during genetic counselling is the procedure-related risk of these techniques.

RECENT FINDINGS: The possible factors modifying the specific risk of the actual fetus are discussed, together with factors that have an impact on procedure-related fetal loss and other complications. Risk factors regarding twin pregnancies, first and second-trimester chorionic villus sampling, early and mid-trimester amniocentesis are discussed separately. New developments have recently occurred in the laboratory techniques used in prenatal diagnosis. Their impact on genetic counselling and the employment of invasive techniques are also addressed.

SUMMARY: During genetic counselling, an individually tailored risk assessment needs to be established before any invasive procedure. This should take into account all the factors modifying the specific risk for aneuploidy or other disorders of the fetus, as well as the actual procedure-related risks.