Increased incidence of placenta praevia and accreta with previous caesareans--a hypothesis for causation.

With the increasing numbers of caesareans, long-term complications, such as anterior placenta praevia-accreta are becoming important. Two case reports are presented here, leading to a hypothesis that the increasing incidence of anterior placenta praevia after prior caesareans may be a result of excessive differential development of the lower uterine segment. This could result from marked stretching of a poorly-healed myometrial area by the developing placenta. This would explain the lower incidence of 'apparent' migration of low placenta, as well as the higher likelihood of morbid adhesion. Although different operative techniques do not have a significant effect on short-term outcomes of caesareans, they are likely to impact the long-term complications. In the absence of long-term studies and good quality evidence, theoretical and logical analysis suggests that adherence to good surgical techniques, such as gentle tissue handling, haemostasis, good myometrial approximation without compromising blood supply and restoration of normal anatomy, may reduce long-term complications.