Perineal massage

Antenatal perineal massage (APM) or birth canal widening (BCW) is the massage of a pregnant woman's perineum around the opening to the vagina, performed anywhere in the 4 to 6 weeks before childbirth and usually on 4-6 separate occasions. The practice aims to more gently mimic the massaging action of a baby's head on the opening to the birth canal prior to birth, which enables some of the hard work of labour to be done before the start of labour. The intention is to attempt to prevent tearing of the perineum during birth, and reduce the need for an episiotomy or an instrument (forceps or vacuum extraction) delivery.

The Oxford Radcliffe NHS Trust Document "Antenatal Perineal Massage" 2011 describes the use of the pregnant mother's thumbs being placed just inside the birth canal, whilst she stands with one foot supported on the toilet. She pulls backwards towards her spine, whilst relaxing her pelvic floor, progressively increasing the pressure under her finger tips until this starts to feel uncomfortable. On the next occasion she uses both thumbs pulling backwards and then sideways, thumbs away from each other, to enlarge the 2 cm diameter opening of the birth canal progressively over time to 10 cm. It is not possible to stretch this opening further causing damage, because this will be limited by the distance between the bony walls of the pelvis.

The goal of APM is to prevent the baby's head from undergoing excessive strain during the last 30 minutes of labour. It seeks to train the mother to relax her pelvic floor to allow the baby's head to pass through the opening, to stretch the two fibrous layers within the Uro-Genital Membrane, a triangular shaped muscular shelf at the front half of the opening of the bony pelvis, through which the 2 cm diameter birth canal and urethra pass, and to transform the fat packed rigid skin at the opening to the birth canal into paper thin stretchy elastic skin, all without using the baby's head.

If the external skin (perineal skin) opening has been stretched before birth, to 10 cm, then there is no reason to perform an episiotomy to increase the diameter of the opening of the birth canal. Tearing is less likely as the external skin at the opening has been stretched already and is lax, whilst the underlying muscular pelvic floor has not been damaged. Episiotomy permanently damages the pelvic floor muscle, as the episiotomy cuts through the nerve supply to this muscle, so the larger part of the pelvic floor muscles atrophies and becomes replaced by scar tissue, increasing the mother's chance of developing a prolapse in the future. Antenatal Perineal Massage does not damage the pelvic floor, so protects against a prolapse.

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Wikipedia