A procedure in OBSTETRICS consisting of turning the FETUS in the UTERUS if the former is lying in an abnormal position which may make eventual delivery difficult. In particular, version (which can take place spontaneously) may be done on a fetus between the 34th and 37th weeks of pregnancy if its buttocks rather than its head are positioned at the cervical end of the uterus. The procedure carries a small risk of precipitating premature labour, and it is not always successful, in which case a breech delivery is attempted or, in difficult cases, a CAESAREAN SECTION is performed. (See PREGNANCY AND LABOUR.)