It is important to differentiate if you have an acute or chronic anal fissure. The reason being that chronic anal fissures might need surgery in the course of treatment and this involves cutting the anal sphincters.
The concern with normal vaginal delivery is the potential damage it might cause to your pelvic floor muscles, which includes the anal muscles. This damage from childbirth, coupled with the potential damage from the anal surgery for a chronic anal fissure can lead to stool incontinence.
I would advise you to seek a specialist opinion on your anal fissure and discuss with your obstetrician the best option of delivery for your condition.
Thank you.
