MODEL RELEASED. Amniotic cell cultures. Technic- ian with petri dish cultures of amniotic cells which have been taken from a pregnant woman. The cells are about to be extracted (harvested) from a nutrient gel. They will be analysed to check that the developing foetus does not suffer from genetic disorders such Down's Syndrome or cystic fibrosis. The cells were obtained by removing some of the amniotic fluid which surrounds the foetus by a procedure known as amniocentesis. During amnio- centesis, which is usually performed between 16-18 weeks pregnancy, about 20-30 millilitres of fluid is removed. The cells in the fluid are then cultured for up to 30 days before analysis.