Surgical insertion of a hollow needle through the abdominal wall into the uterus of a pregnant female to extract fluid from the amniotic sac for analysis of fluid and fetal cells.
This can reveal the fetus's sex (important when sex-linked genetic disease is possible), chromosomal disorders, and other problems. First performed in the 1930s, amniocentesis is generally done under local anesthesia in the 15th–17th week of gestation.