**5. External cephalic version (ECV): Concept and history**

The external cephalic version is an obstetrics performance aiming at turning a breech presentation into a cephalic one, more favourable to vaginal delivery. It can also be used to turn a transverse situation into a longitudinal (breech or cephalic) presentation. However, its current use is exclusively aimed at turning breech presentation into cephalic presentations.

This performance was widely used before 1970s, but it began to decline because it was considered an unsafe method. It has been performed from the time of Hippocrates (460-377 BC). Aristotle (384-322 BC) was the author of some texts describing that many doctors advised midwives to handle the baby's head so that it was presented at birth.

Over the last century, this performance gradually rose until the sixties, when it saw a boom caused by the increasing demand for a less medical intervention at birth. Before the seventies, the cephalic version was performed preterm because it was believed that this process could hardly be successful if it was performed at term. The external cephalic version was included in the daily obstetric practice due to the obvious and immediate effectiveness of the process as well as the results from non-randomized clinical projects. Its popularity began to decline in the mid-seventies due to the doubts raised about its effectiveness and safety. Reports about a considerable perinatal mortality associated to this performance were published (Bradley Watson, 1975) and the caesarian delivery was presented as the safest option against the external cephalic version or breech presentation. That is the reason why this practice was gradually abandoned until becoming an unusual performance. It must be considered that in those times there were neither ultrasound scans nor antenatal monitoring. performance

Subsequent projects proved that the external cephalic version in breech babies at term significantly reduced non cephalic presentation at birth as well as the rates of caesareans with no worse perinatal outcome. This situation, as well as the implantation of the Term Breech Trial's results made the external cephalic version be considered as the best option in order to avoid the caesarean in breech babies at term.
