Statistics from many delivery units has shown that two-thirds of sphincter tears occur during spontaneous vaginal deliveries.  One-third of sphincter tears occur during instrumental deliveries, with for example forceps or vacuum.

It is important for every doctor/midwife to know their statistics.  You should go through your deliveries from the past five to ten years and count the amount of sphincter tears compared to all your deliveries. By doing this you can conclude how much you have to change the way you handle your deliveries.