A delivery with forceps from "Die Einfuhrung des rechten Loffels. Scanzoni 1855.
Risk factors to grade 3 and 4 tears:
First vaginal delivery
Instrumental delivery (vacuum, forceps)
Big baby, over 4 kg
Long lasting delivery
Oxytocin augmentation
Earlier grade 3 or 4 tear
Mathernal age, age over 35 years increases the risk sligthly
Epidural analgesia
Poor perineal support
Incorrect episiotomy
Water birth