Introduction During pregnancy, due to the influence of poor lifestyle and environmental pollution, the probability of fetal abnormalities is relatively high. In order to ensure the health of the fetus, many pregnant women choose to undergo two common prenatal diagnostic tests – chorionic villus puncture and amniocentesis. Although they are relatively similar in terms of fetal testing, they are different. This article explains how they differ. 1. The villi and amniotic fluid at the surgical site are two different placental tissues.