A prenatal test to detect birth defects that is performed at an early stage of pregnancy and involves retrieval and examination of tissue from the chorionic villi. Also called chorionic villus biopsy绒毛膜绒毛取样：一种胎儿期检查，以发现怀孕早期的胎儿缺陷，并恢复和检查被卵膜绒毛包着的组织 也作 chorionic villus biopsy