The prevalence of low back pain (LBP) and pelvic girdle pain (PGP) is estimated to be 56% to 72% in the prepartum female population (1). Overall, nearly 50% of pregnant women report PGP before 20 weeks’ gestation, and in late pregnancy the incidence can reach 70%.

Pelvic girdle pain (PGP) is defined as “pain between the posterior iliac crest and the gluteal fold, especially near the sacroiliac joint. The pain may radiate to the back of the thigh and be associated with pain in the pubic symphysis. PGP refers to pain that occurs in the muscles, ligaments, and joint capsules in the pelvic region. The pain occurs after 18 weeks and peaks at 24 to 36 weeks. Although often confused with low back pain, PGP is characterized by pain between the posterior iliac crest and gluteal fold, particularly in the sacroiliac joint (SIJ). In addition, symphysis pain is commonly reported in pregnancy-related PGP, which is not seen in low back pain.

The multifactorial etiology of PGP remains poorly understood, complicating recovery for many women. The combination of hormonal and biomechanical aspects, inadequate motor control, and stress on ligamentous structures are the most common hypotheses for the development of PGP. In the physiotherapy of PGP, some important structures are the bony pelvis and the myofascial system of the anterior abdominal wall, especially the separation of the pubic symphysis and rectus abdominis (DRA). Pregnancy-related changes in the rectus abdominis have been shown to be associated with decreased abdominal muscle performance in controlling pelvic motion against resistance (2).

Approximately half of women with initially manifest LBP during pregnancy still have pain 1 year after delivery, and 20% have symptoms 3 years after delivery. LBP and PGP may be caused by biomechanical changes during pregnancy, but we also need to think more about hormone levels and their effects on myofascial tissue. As hormone levels increase during pregnancy, myofascial tissue becomes more flexible. After administration of β-estradiol, collagen-I decreases from 5.2 to 1.9%, while collagen III and fibrillin increase. This change in extracellular matrix (ECM) composition allows tissues to adapt during pregnancy. Rigid fascia can help stabilize the sacroiliac joint and spine – loose fascia can cause the pelvic or lumbar pain typical of pregnancy (3) (4).

Martyna Kasper-Jędrzejewska

References:

1. Fogarty S, McInerney C, Hay P. Pregnancy-related Pelvic Girdle Pain and Pregnancy Massage: Findings from a Subgroup Analysis of an Observational Study. Int J Ther Massage Bodyw. maj 2020;13(2):1–8.
2. Aldabe D, Lawrenson P, Sullivan J, Hyland G, Bussey MD, Hammer N, i in. Management of women with pregnancy-related pelvic girdle pain: an international Delphi study. Physiotherapy. czerwiec 2022;115:66–84.
3. Smith M, Galbraith W, Blumer J. Reducing Low Back and Posterior Pelvic Pain During and After Pregnancy Using OMT. J Am Osteopath Assoc. 1 lipiec 2018;118(7):487–8.
4. Wiezer M, Hage-Fransen M a. H, Otto A, Wieffer-Platvoet MS, Slotman MH, Nijhuis-van der Sanden MWG, i in. Risk factors for pelvic girdle pain postpartum and pregnancy related low back pain postpartum; a systematic review and meta-analysis. Musculoskelet Sci Pract. sierpień 2020;48:102154.