Is a CVS (chorion villus sampling) more risky than an amniocentesis?
This depends. The evidence suggests that if the procedures are carried out in fetal medicine units or by specialists who are trained in invasive procedures and perform them frequently, the additional risk of miscarriage (over and above the 'background' rate) should be less than 1% for either CVS or amniocentesis. Each unit should be able to provide their own audited miscarriage risk figures for the previous years.