Perineal Tears and Birth Preparation
The perineum is the area between the vagina and anus. Just below the surface of the skin, is a structure called the perineal body - a pyramid-shaped, fibromuscular structure. But why is this so relevant?
The perineal body serves as an important attachment site for various muscles, including:
the deep pelvic floor
the superficial pelvic floor
the external anal sphincter
the transverse perineal muscles
urethral sphincter muscle fibres
The relevance of this is that if a perineal tear is sustained during a vaginal delivery, it has a knock-on effect that may result in dysfunction in one or more of those muscles.
Around 85% of women who undergo a vaginal delivery will experience some degree of tearing. Perineal tears are categorised as follows:
—> Grade 1 = tearing to the vaginal mucosa or perineal skin only
—> Grade 2 = tearing of the perineal muscles
—> Grade 3A = where <50% of the external anal sphincter is torn
—> Grade 3B = where >50% of the external anal sphincter is torn
—> Grade 3C = where the external and internal anal sphincters are torn
—> Grade 4 = tearing extending through the anal epithelium (resulting in communication between the vaginal and anal epithelium)
There are various factors that contribute to the risk of sustaining a higher degree tear. These include:
shortened perineal length (<25mm)
large fetal weight (>4kg)
instrumental delivery (forceps)
prolonged 2nd stage (pushing phase) labour >60mins
ethnicity
increased maternal age
Physiotherapy has a role in helping determine how significant these risk factors may be, whilst also being able to help you prepare the perineum for delivery, thereby reducing your risk of tearing or episiotomy. Perineal massage, breathing and pushing techniques, pelvic floor strengthening during pregnancy (yes this will reduce your risk, not make your pelvic floor tighter!) are all things we can help teach your in order to minimise your risk of sustaining a tear during delivery.
