Prenatal diagnosis is possible using amniocentesis or chorionic villus sampling. Common diagnosis procedures include amniocentesis and chorionic villus sampling. Prenatal diagnosis is possible by chorionic villus sampling or amniocentesis. Chorionic villus sampling is a prenatal procedure which involves a placental biopsy. Triple X syndrome can be diagnosed prenatally through amniocentesis or chorionic villus sampling. Turner syndrome may be diagnosed by amniocentesis or chorionic villus sampling during pregnancy. Chorionic villus sampling retrieves placental tissue in either a transcervical or transabdominal manner. Amniocentesis and chorionic villus sampling (CVS) are procedures conducted to assess the fetus. Because amniocentesis and chorionic villus sampling are invasive, they have a chance of causing miscarriage. There are two types of chorionic villus sampling. Moreover, basal lamina of follicle-associated epithelium is more porous compared to intestinal villus. They are covered with small finger-like projections called villi (singular, villus). Each of these microvilli are much smaller than a single villus. Each villus, in turn, is covered with microvilli. It has also been observed to cause villus ischemia, and increase intestinal motility.