Here we will consider some of the reasons for low back, gluteal (buttock) and pelvic pain during pregnancy, and why it may continue after giving birth.
(According to an admittedly ancient (1994) study, more than 67% of women experienced back pain just after delivery, while 37% said they had back pain at a follow up examination at least twelve months later (1).
More recent data indicates that up to 75% of women who suffer from low back pain during pregnancy may continue to have pain after birth, or postpartum (2, 3, 4, 5, 6, 7).
Evolutionarily-speaking, the shift from moving around on all fours to two legs required a number of compromises, trade-offs, and (to be honest) bodgy quick-fixes that would embarrass the shonkiest unlicensed contractor.
Shortly put, the pelvis got narrower to accommodate to the changed way of moving, which in turn reduced the amount of space for the baby's head as it, ahem, exits the body. This occurred at the same time that human brains were getting larger, which poses an obvious problem.
Note, however that relaxin, as a hormone, affects everywhere in the body (and indeed plays a role in the management of blood pressure and flow, and tissue repair as well as affecting the joints and ligaments).
Furthermore, high levels of relaxin may be related to joint laxity and instability, but the relationship is uncertain; with some studies showing a relationship between higher relaxin and progesterone levels in pregnant women with PGP syndrome (9, 10, 11), and others, well, not (12, 13, 14).
In either case, the joints in the low back and pelvis get a serious work-out during pregnancy and delivery, and combined the biomechanical changes in posture and walking through this period (some of which will continue into the postpartum period), it is perhaps not surprising that around one in five women will experience LBP/PGP either during or after pregnancy (or both), and, again, around twenty percent of these will report continuing pain months or even years later (1, 15).
This reduces the body's ability to support the pelvis and low back, and may contribute significantly to postpartum low back and pelvic pain - in one study, over half of women with pregnancy-related low back and pelvic pain had pelvic floor dysfunction (16).
To add another dimension, there has been some suggestion that high relaxin levels are related to pelvic floor dysfunction (17)!
According to the study in Anaesthesiology, a history of low back pain (no revelations there!), greater weight, and slightly more surprisingly, younger age are among the associations for postpartum low back pain (8).
Unluckily for the vertically challenged among us, shorter stature was also associated with new-onset postpartum back pain (ibid).
Once your osteopath or healthcare provider has eliminated other common causes of low back pain such as the intervertebral discs or facet joints, as well as more uncommon but concerning conditions with complicated names such as osteomyelitis or cauda equina syndrome, they will undertake a full assessment of the biomechanics and postural adaptations/mechanisms of the affected and surrounding areas.
Stone, C. (2007) Visceral & Obstetric Osteopathy, Churchill LIvingstone
(1) Ostgaard HC, Andersson GB. (1992)
"Postpartum low-back pain"
(2) Stapleton DB, MacLennan AH, Kristiansson P (2002) The prevalence of recalled low back pain during and after pregnancy: a South Australian population survey. Aust N Z J Obstet Gynaecol 42: 482-485.
(3) Turgut F, Turgut M, CetinÅŸahin M (1998) A prospective study of persistent back pain after pregnancy. Eur J Obstet Gynecol Reprod Biol 80: 45-48.
(4) Líndal E, Hauksson A, Arnardóttir S, Hallgrímsson JP (2000) Low back pain, smoking and employment during pregnancy and after delivery - a 3-month follow-up study. J Obstet Gynaecol 20: 263-266.4. Ansari NN, Hasson S, Naghdi S, Keyhani S, Jalaie S (2010) Low back pain during pregnancy in Iranian women: Prevalence
(5) Bastiaenen CH, de Bie RA, Vlaeyen JW, Goossens ME, Leffers P, et al. (2008) Long-term effectiveness and costs of a brief self-management intervention in women with pregnancy-related low back pain after delivery. BMC Pregnancy Childbirth 8: 19.
(6) Breen TW, Ransil BJ, Groves PA, Oriol NE (1994) Factors associated with back pain after childbirth. Anesthesiology 81: 29-34.
(7) Gutke A, Lundberg M, Östgaard HC, Öberg B (2011) Impact of postpartum lumbopelvic pain on disability, pain intensity, health-related quality of life, activity level, kinesiophobia, and depressive symptoms. Eur Spine J 20: 440-448.
(8) Breen TW1, Ransil BJ, Groves PA, Oriol NE (1994)
"Factors associated with back pain after childbirth"
Anesthesiology. 1994 Jul;81(1):29-34
(9) Lubahn J, Ivance D, Konieczko E, Cooney T
"Immunohistochemical detection of relaxin binding to the volar oblique ligament"
J Hand Surg Am. 2006 Jan; 31(1):80-4.
(10) Dragoo JL, Castillo TN, Braun HJ, Ridley BA, Kennedy AC, Golish SR (2011)
"Prospective correlation between serum relaxin concentration and anterior cruciate ligament tears among elite collegiate female athletes"
Am J Sports Med. 2011 Oct; 39(10):2175-80.
(11) Dragoo JL, Castillo TN, Korotkova TA, Kennedy AC, Kim HJ, Stewart DR (2011)
"Trends in serum relaxin concentration among elite collegiate female athletes"
Int J Womens Health. 2011 Jan 19; 3():19-24.
(12) Ohtera K, Zobitz ME, Luo ZP, Morrey BF, O'Driscoll SW, Ramin KD, An KN (1985)
"Effect of pregnancy on joint contracture in the rat knee"
J Appl Physiol (1985). 2002 Apr; 92(4):1494-8.
(13) Arnold C, Van Bell C, Rogers V, Cooney T (2002)
"The relationship between serum relaxin and knee joint laxity in female athletes"
Orthopedics. 2002 Jun; 25(6):669-73.
(14) Wolf JM, Williams AE, Delaronde S, Leger R, Clifton KB, King KB (2013)
"Relationship of serum relaxin to generalized and trapezial-metacarpal joint laxity"
J Hand Surg Am. 2013 Apr; 38(4):721-8.
(15) Norén L, Ostgaard S, Johansson G, Ostgaard HC. (2002)
"Lumbar back and posterior pelvic pain during pregnancy: a 3-year follow-up"
Eur Spine J. 2002;11(3):267-271.
(16) Pool-Goudzwaard AL, Slieker ten Hove MC, Vierhout ME, Mulder PH, Pool JJ, Snijders CJ, Stoeckart R. (2005)
"Relations between pregnancy-related low back pain, pelvic floor activity and pelvic floor dysfunction"
Int Urogynecol J Pelvic Floor Dysfunct. 2005;16(6):468-474
(17) Harvey MA, Johnston SL, Davies GA (2008)
"Mid-trimester serum relaxin concentrations and post-partum pelvic floor dysfunction"
Acta Obstet Gynecol Scand. 2008; 87(12):1315-21.