Patient Guide: Pelvis / Sacroiliac Instability & Low Back Pain During Pregnancy

By: Lindsay Davey, MScPT, MSc, CDT
May 24, 2017
Editors: Ryan Davey, PhD and Lindsay Davey, MScPT, MSc, CDT

Woman holding baby without pelvis / sacroiliac instability or low back pain after pregnancy
The biological necessity for rapid growth during pregnancy creates unique physical demands on the pelvis. So it’s not surprising that many women experience some degree of discomfort or pain in their pelvis and/or low back during their pregnancies or soon after birth.

It is estimated that nearly 70% of pregnant women experience low-back pain, and 20% experience pelvic pain (ref 1).  This pain tends to increase as pregnancy progresses, and can interfere significantly with sleep and daily activities. Approximately 10% of these women continue to experience significant lumbo-pelvic pain and dysfunction a year and a half after delivery, which can become chronic (ref 1,2).

Numerous risk factors can contribute to the development of pelvic and low back pain, however, some general treatment and self-care principles can be applied with good results.

The simple self-help measures outlined below can be effective at preventing or alleviating mild to moderate cases of pelvis and low back pain.

Unfortunately some women’s conditions may deteriorate to a more painful and debilitating form of pelvic instability that requires more targeted methods. For such cases, hands-on physiotherapy including gentle manual therapy and patient-specific exercises can be very effective.

Causes of Pelvic / Low Back Pain During and After Pregnancy

  1. The release of a pregnancy hormone called relaxin causes the ligaments in your pelvis and other joints to soften or loosen.  This enables the pelvic bones to shift in order to accommodate the growth of the baby, and prepare for delivery. This is obviously beneficial; however, relaxin can also contribute to an ‘unlocking’ or ‘instability’ in normally very stable pelvis joints (called the sacroiliac joints).
  2. Weight gain that occurs during the normal course of pregnancy rapidly increases the general load on low back and pelvic joints, ligaments, and muscles, making them more susceptible to injury.
  3. Weight gain in the abdominal area is particularly problematic, disrupting the mother’s normal standing and walking posture, and thereby increasing strain at the low back, pelvis, and buttocks.
  4. After the baby is born there is an increase in high-risk activities including bending over, lifting, and carrying (among other repetitive physical tasks), which the body is likely not accustomed to.
  5. Initiating a regular postpartum exercise program prematurely can further exacerbate pelvic and low back pain (see “5 Signs You’re Not Ready for Postpartum Exercise“).

Symptoms of Pelvis / Sacroiliac Instability

  1. Pain is often felt in the buttocks, usually between the tailbone and low-back, and is often one-sided.
  2. Pain can radiate into the front of the pelvis, into the hips, and/or down the back of the thigh (often misdiagnosed as sciatica).
  3. One or both legs may feel excessively weak, with less tolerance to weight bear, and you may have difficulty lifting the leg when lying down.
  4. Certain activities may aggravate the pain:  turning in bed, walking, moving from sitting-to-standing, bending forward, stairs, getting dressed/undressed.
  5. Pain may be worse at the end of the day, or overnight, and may be related to your activity level that day.

Self-Help Treatment and Prevention Tips for Pelvis Pain / Sacroiliac Instability

  1. Avoid one-legged standing tasks, or standing where your body weight is unevenly distributed between each leg.
  2. Change your position in bed by sitting upright, then turning (versus planting one foot on the bed to push and roll, which may be aggravating).
  3. Sit down to put on pants, socks, etc.
  4. Contract your lower abdominal and pelvic floor muscles prior to lifting, sneezing, coughing, or other exertion.
  5. Use a pelvis support belt (or a cane as needed) if walking is particularly painful, until symptoms subside.

Physiotherapy Treatment of Pelvis Pain / Sacroiliac Instability

The causes and treatment of low-back and pelvic pain during pregnancy remains an active area of clinical research, but unfortunately good studies are still lacking.

The best clinical evidence suggests that targeted exercise tailored to the stage of pregnancy and delivered along with education can significantly reduce pain and disability in pregnant women suffering from low-back and pelvic pain (ref 1). Interestingly, the same benefit was not seen with group-based exercise classes.

Various other treatment interventions have been investigated, but due to inadequate study sizes and designs, definitive evidence of benefit remains lacking. These include: acupuncture, yoga, pelvic support belts, craniosacral therapy, etc. (ref 1).

Your physiotherapist may employ tools and techniques including:

  1. Education on cues to stabilize your pelvis before performing a limb or low back movement which may be aggravating; education on movement patterns or positions to avoid. Strategies to perform functional tasks such as turning in bed, getting dressed/undressed, or climbing stairs, without provoking pain.
  2. Exercise instruction focused on training the stabilizing muscles of the pelvis and low back including the lower abdominals, pelvic floor, and spinal stabilizing muscle groups.
  3. Gentle mobilization of stiff joints in the hip, back, or pelvis which may be contributing to the ‘looseness’ found elsewhere.
  4. Soft tissue techniques to relieve strained muscle groups.
  5. Acupuncture
  6. Product suggestions including pelvis support belts to aid in self-management.

Seeking out a physiotherapist with specialization in Pelvic Floor Physiotherapy may be especially effective.


  1. Liddle S.D., and Pennick V. Interventions for preventing and treating low-back and pelvic pain during pregnancy. Cochrane Database Syst Rev. 2015 Sep 30;(9).
  2. Elden H., Gutke A., Kjellby-Wendt G., et al. Predictors and consequences of long-term pregnancy-related pelvic girdle pain: a longitudinal follow-up study. BMC Musculoskelet Disord. 2016 Jul 12;17:276.

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