[2] The affection appears to consist of relaxation of the pelvic articulations, becoming apparent suddenly after parturition or gradually during pregnancy and permitting a degree of mobility of the pelvic bones which effectively hinders locomotion and gives rise to the most peculiar and alarming sensations.Prior to the 20th century, specialists of pregnancy-related PGP used varying terminologies.
Mens (2005)[3] A combination of postural changes, the position and weight of the baby, unstable pelvic joints under the influence of pregnancy hormones, and changes in the centre of gravity can all add to the varying degrees of pain or discomfort.
Women with PGP may begin to waddle or shuffle, and may be aware of an audible clicking sound coming from the pelvis.
During pregnancy and postpartum, the symphyseal gap can be felt moving or straining when walking, climbing stairs or turning over in bed; these activities can be difficult or even impossible.
She may experience pain involving movements such as dressing, getting in and out of the bath, rolling in bed, climbing the stairs or sexual activity.
In case the muscles around the joint do not function, the patient will experience pain and weakness when performing everyday activities.
This type often occurs after giving birth to a child weighing 3000 grams or more, in cases of hypermobility, and sometimes after an accident involving the pelvis.
Sometimes a small accident occurring long before giving birth is forgotten so that the pelvic instability is attributed only to the childbirth.
[5] Other psychosocial risk factors associated with woman experiencing PGP include higher level of stress, low job satisfaction and poorer relationship with spouse.
PGP disorder is complex and multi-factorial and likely to be also represented by a series of sub-groups driven by pain varying from peripheral or central nervous system,[9] altered laxity/stiffness of muscles,[10] laxity to injury of tendinous/ligamentous structures[11] to 'mal-adaptive' body mechanics.
[12] Pregnancy begins the physiological changes through a pattern of hormonal secretion and signal transduction thus initiating the remodelling of soft tissues, cartilage and ligaments.
The pubic symphysis has a fibrocartilage joint which may contain a fluid filled cavity and is avascular; it is supported by the superior and arcuate ligaments.
During pregnancy relaxin has a diverse range of effects, including the production and remodelling of collagen thus increasing the elasticity of muscles, tendons, ligaments and tissues of the birth canal in view of delivery.
Although relaxin's main cellular action in pregnancy is to remodel collagen by biosynthesis (thus facilitating the changes of connective tissue) it does not seem to generate musculoskeletal problems.
To avoid pain on weight bearing structures a very short stance phase and limp occurs on the injured side(s), this is called Antalgic Gait.
For most women, PGP resolves in weeks after delivery but for some it can last for years resulting in a reduced tolerance for weight bearing activities.