The site of placental attachment as a factor in the aetiology of breech presentation.

The frequency of cornu-fundal implantation of the placenta in association with breech presentation was investigated in the following study. In a series of 124 women with breech presentation, and 125 women with cephalic presentation at or near term, the implantation site of the placenta was demonstrated by ultrasonography. It was found that with breech presentation the placenta was implanted in the cornual region in 72.6% of the cases, as compared with 4.8% in cephalic presentation. The placental implantation site may therefore have a determining effect upon the presentation of the foetus.