PERINEAL TEARS AFTER CHILDBIRTH

Written by Dr.M.D.Mazumdar, MD

The perineum is the region between the vaginal opening and the anus. The perineum may get injured when there is overstretching or rapid stretching during the delivery of the baby.

Tears are more common in women in their first childbirth since the perineum is quite firm and cannot stretch adequately. While an episiotomy can prevent major perineal tears to some extent, tears can still occur even after or with an episiotomy.

Very often, after an episiotomy has been done, a tear can occur at its apex, extending it upwards and to various depths in the mucosa and muscle.

An inelastic perineum due to the presence of a scar can also lead to a perineal tear. Some of the causes of overstretching of the perineum leading to perineal tear are:

• A big baby compared to the size of the mother's pelvis.
• Malpresentation of the baby like occipitoposterior position or face presentation.
• Average sized baby with a narrow maternal vaginal outlet
• Forceps delivery or other instrumental deliveries
• Shoulder Dystocia

Degrees of Perineal Tear

There are four degrees of perineal tear, depending on the extent of the tear. The third degree perineal tear is further subdivided into three subcategories.

• First Degree Perineal Tear

  This is only a mild degree of laceration or tear of the skin at the edge of the vaginal opening. The lower part of the vagina as well as the perineal skin may be torn but the major muscles of this region are not affected. It is also known as a Vaginal Tear.

• Second Degree Perineal Tear

  This involves rupture of the muscles of the perineum with deep tears in the vaginal wall. The tear extends beyond fourchette, perineal skin and vaginal mucosa to perineal muscles and fascia and may extend right up to the anus, but it does not involve the anal sphincter.
  

• Third Degree Perineal Tear

  In this type of perineal tear, the tear extends from the vaginal opening through the posterior vaginal wall and the perineal muscles upto the anus with injuries to the external anal sphincter. The anal or the rectal canal may or may not be involved. The third degree tear is divided into three subcategories, depending on the extent of involvement of the anal sphincter:
  • 3A: There is partial tear of the external anal sphincter involving less than 50% of its thickness.
    
  • 3B: Greater than 50% of the external anal sphincter is torn but the internal anal sphincter is not affected.
    
  • 3C: The internal anal sphincter is also torn.

• Fourth Degree Perineal Tear

  The fourchette, perineal skin, vaginal mucosa, muscles, anal sphincter, both external and internal as well as the rectal mucosa are torn. This type is also called a complete perineal tear.
  

Management/Treatment of Perineal Tears

Prevention is the best management. The second stage of labour should be properly conducted. An episiotomy should be performed wherever deemed necessary to prevent tear of the perineum.