By Kirrily Curran (Women's Health Physiotherapist, physiozest)
I am a firm believer in the phrase that knowledge is key. This information is not to scare you, not to place fear into your birth experience, but to empower you to ask questions and make informed decisions with your birth provider prior to and during the birth experience.
When we talk about vaginal birth, we are talking about giving birth through the vaginal canal, stretching the pelvic floor muscles 3 x their natural resting length. Most muscles will injure at 1.5 x their resting length, so the pelvic floor is pretty incredible to be able to withstand this!
Injuries that occur giving birth are all due to the body trying to make more space for the baby to travel downwards and exit the vagina. Injuries can be either bony or to the soft tissues including muscles, ligaments and fascia.
Risk factors for birth injury:
- older Maternal age
- first birth or VBAC (vaginal birth after C-section)
- Newborn weight over 4kg (or large weight/size for mothers’ size)
- abnormal delivery presentation such as breech or shoulder dystocia
- a very quick or very long labour
- prolonged second stage of labour
- instrumental deliveries
- epidural or oxytocin use
PELVIC FLOOR INJURIES
More than 85% of females who undergo a vaginal birth will suffer some degree of perineal tear.
Grade 1- Shallow tear to the Skin of perineum
Grade 2- tear to the skin and muscle of the perineum
Grade 3- tear through the perineal muscles and into the external anal sphincter (EAS)
Grade 4- tear extends through the EAS and into the anus
A Levator ani avulsion is where the pelvic floor muscles, particularly the front of the puborectalis muscle, pulls away from the back of the pubic bone. This can be a partial avulsion where some fibres remain attached or a complete tear where all fibres have been detached. This can occur on one side (unilateral) or both sides (bilateral) of the muscle.
A Levator Ani avulsion can enlarge the opening of the pelvic floor hiatus by about 25%. If we don’t have good tension and muscle support at the bottom of the pelvis or the space is widened, the organs have little support to stay up in the pelvis in their natural position and can descend downwards into the vaginal space. A Levator Ani avulsion increases the risk of long term bladder prolapse by about 50% and uterine prolapse by 75%.
PELVIC ORGAN PROLAPSE
Types of prolapse include bladder (cystocele), uterus (uterine), rectal (rectocele), bowel (enterocele).
Both pelvic floor damage and pelvic floor prolapse can result in short and long-term complications for women. Urinary and faecal incontinence, urinary urgency and retention, sexual pain and dysfunction and chronic pelvic pain are all consequences of birth injuries.
INSTRUMENTAL DELIVERY
A forceps delivery is the use of a large tong like tool placed either side of babies’ head to assist in guiding the baby down the vaginal canal for delivery. Forceps delivery is often recommended when birth is not progressing, or if baby is in distress and a quick birth is deemed necessary. A ventouse delivery is the use of a small vacuum like device placed on the baby’s head in the birth canal to assist baby’s delivery. Unfortunately, both vacuum and forceps delivery have substantially greater risk of pelvic injury.
CASCADE OF INTERVENTION
The cascade of intervention describes the link between obstetric interventions and medications and their possible consequences.
It has been reported that inductions may increase the risk of birth complications by 50% and adding an epidural increases the risk to 60%.
Epidural analgesia provides very effective pain relief during labour. However, it has been shown that epidural pain relief increases the risk of a long labour, reduces the ability for a birthing women to move and may promote an ineffective 2nd stage of labour. This in turn may increase the use of vacuum and forceps use leading to increased risk of birth injury and long-term complications.
WOMEN'S HEALTH PHYSIO
Women’s health physio’s are trained to provide education and management options in the post-partum period. Some women’s health physio's are trained in fitting pessaries.
Although we may be unable to correct tissue damage caused by birth injuries, we have many treatment tools and options so that women can be asymptomatic following birth injury and prolapse diagnosis. Early intervention is key to optimal recovery and learning to manage your injury and symptoms in the long term.