An episiotomy is an iatrogenic wound created in the virginal wall during child birth to enable easy passage of the baby. This is usually done for first time mothers to prevent tear of the vaginal wall. An episiotomy wound can easily be repaired!

Episiotomy wounds usually heal very fast due to the adequate blood supply in the vaginal wall. However, it is not uncommon to have breakdown of sutured episiotomy wounds and a very common cause is the use of sitz bath from my observation. The reason for this is understandable. Episiotomy wounds are usually closed using absorbable sutures which are easily dissolved by warm water.
Therefore, it is advisable to stay clear Sitz bath or warm water massage around the virginal for about one week if you have a sutured episiotomy wound to avoid wound breakdown.
Other causes of episiotomy wound breakdown include:

Infection: This is not very common due to the availability of antibiotics and early repair of the wound.
Poor suture technic: It is possible to pick up the wall of the rectum during repair and this can lead to fistula formation.

For more information, visit:

http://www.droleo.com/2017/07/effect-of-sitz-bath-on-sutured.html?m=1