Intraoperative scanning for placental location

Intraoperative ultrasound scanning to locate the upper edge of the placenta

Intraoperative ultrasound scan

Making an incision well away from the placental bed is extremely important. To ensure that it is not accidentally transected a senior obstetrician may perform an intra-operative ultrasound scan (USS) of the uterus to identify the upper placental edge. The probe is a standard USS probe within a sterile probe cover. An assistant operates the ultrasound machine.

Once clearly visualised on scan, the upper border of placenta can be marked on the anterior and lateral surfaces of the uterus using the coagulation-monopolar diathermy pencilette (small diathermy marks are left on the serosa to demarcate the underlying placenta).

The incision can then placed well above these markings to ensure that the edge of the placenta is not disturbed at delivery as this could provoke significant haemorrhage.