It involves using a needle to collect samples of the embryonic structure that goes on to form the placenta.
The process can be performed as early as 10 weeks into pregnancy. In this study, researchers found strawberry hemangiomas in 12 of 95 cvs exposed infants compared with 3 of 87 infants who had been exposed to amniocentesis which is typically performed later in pregnancy.
But scientist's reporting in the Journal of Craniofacial Surgery say because cvs detects serious genetic diseases such as Down's Syndrome the benefits may outweigh the risks.
