Pelvic Girdle Pain: What Could Be Causing It and What to Do Next

What Exactly Is Pelvic Girdle Pain?

Pelvic girdle pain is discomfort, stiffness, or instability felt anywhere in the bony ring formed by the two sacroiliac joints at the back and the pubic symphysis at the front. The pain may be one-sided or both-sided, and it often spreads into the buttocks, groin, inner thighs, or even the hips. It is distinct from non-specific low back pain, although the two frequently coexist.

The European guidelines on PGP, updated and summarised in a widely cited systematic review, define PGP as pain experienced between the posterior iliac crest and the gluteal fold, with or without radiation, that is confirmed by specific pain provocation tests. That clinical definition matters because it separates PGP from lumbar disc disease, sacroiliac joint arthritis in isolation, or referred visceral pain, all of which require different management.

Why Women Are Disproportionately Affected

The female pelvis is anatomically wider and shallower than the male pelvis, which distributes load differently across the sacroiliac joints during walking. Relaxin, a hormone produced by the corpus luteum and the placenta, loosens ligaments throughout the body. Women produce significant relaxin during the luteal phase of every cycle, not only during pregnancy, which partly explains why PGP can occur outside of pregnancy too. Estrogen also modulates connective tissue stiffness, so any life stage involving estrogen fluctuation, including perimenopause, creates a window of vulnerability.

The Three Main Joint Sites

• Sacroiliac joints (bilateral or unilateral): The most commonly symptomatic site. Pain sits over the dimples at the base of your spine and typically worsens with single-leg loading, rolling in bed, or climbing stairs.
• Pubic symphysis: Pain at the front of the pelvis, sometimes felt as a clicking or grinding sensation. The obstetric term is symphysis pubis dysfunction (SPD).
• Combined pattern: Pain at both the front and back of the pelvis simultaneously. This pattern tends to be the most functionally limiting.

What Causes Pelvic Girdle Pain?

The short answer is that PGP results from abnormal load transfer across the pelvic ring, but the reason that transfer goes wrong differs by life stage and individual physiology.

During Pregnancy

Pregnancy is the single most common context for PGP. A 2008 systematic review covering more than 76,000 women found a pooled prevalence of approximately 20% for PGP specifically and 50% for any pregnancy-related low back or pelvic pain. The causes are multifactorial.

Relaxin and ligament laxity. Relaxin rises sharply in the first trimester, peaks around weeks 10-14, and remains elevated throughout. It softens the cartilage and ligaments around the pubic symphysis and sacroiliac joints, which is biologically necessary to allow the pelvis to expand during birth. In some women, this laxity outpaces the muscle-stabilising capacity of the pelvic floor, gluteal muscles, and deep abdominals, producing micro-instability and pain.

Postural load shift. As the uterus grows, your centre of gravity shifts forward and lumbar lordosis increases. This redirects compressive forces through the posterior SI joints. Biomechanical studies using three-dimensional gait analysis show that pregnant women demonstrate altered sacroiliac joint kinematics from as early as 16 weeks gestation.

Prior history. Women with a previous episode of PGP, a history of low back pain before pregnancy, or a physically demanding job carry a higher risk in subsequent pregnancies.

Outside Pregnancy: The Causes Many Clinicians Miss

WomanRx uses a four-category framework to assess PGP in non-pregnant women, because the differential is broader than most online resources acknowledge:

1. Hormonal and connective tissue changes. Perimenopause brings declining estrogen, which reduces collagen density and alters joint stiffness. This is why some women first notice SI joint pain in their mid-40s without any injury. Relaxin fluctuates across the menstrual cycle, peaking in the luteal phase, and women with hypermobility spectrum disorders or hypermobile Ehlers-Danlos syndrome (hEDS) may notice their pelvic pain worsens the week before their period.

2. Inflammatory arthritis. Axial spondyloarthritis (axSpA) including ankylosing spondylitis disproportionately goes undiagnosed in women because the imaging pattern differs from the classic male presentation. A 2019 analysis in Annals of the Rheumatic Diseases found that women with axSpA wait an average of 8.8 years for diagnosis compared with 6.5 years in men, partly because sacroiliitis on MRI may appear less dramatic. If your pelvic pain is worst in the morning, improves with movement, and wakes you from sleep, ask your clinician specifically about axSpA.

3. Postpartum persistence. For approximately 7% of women, PGP does not resolve after birth and persists beyond 12 months, transitioning to a chronic musculoskeletal condition. The PEPAP study (Pregnancy-related Pelvic And back Pain) followed 870 women and found that severe disability at 3 months postpartum was the strongest predictor of pain still present at 2 years.

4. Trauma, asymmetric loading, and structural causes. A fall directly onto the sacrum, prolonged asymmetric sitting, or a leg-length discrepancy can disrupt load transfer through the pelvic ring in women of any age. Hypermobility, which is more prevalent in women than men, amplifies this vulnerability.

PCOS and Connective Tissue

Women with polycystic ovary syndrome (PCOS) have elevated androgens but also frequently have insulin resistance and low-grade systemic inflammation, both of which affect musculoskeletal tissue quality. While direct trial data specifically linking PCOS to PGP is sparse (an evidence gap worth naming), women with PCOS have measurably lower bone mineral density at the femoral neck compared with age-matched controls, which suggests the entire musculoskeletal framework may be affected differently than in women without PCOS.

How Is Pelvic Girdle Pain Diagnosed?

PGP is diagnosed clinically, through history and specific physical tests. There is no single imaging finding that confirms it, and X-ray is often normal.

Key Provocation Tests

Your clinician will likely use one or more of the following tests:

• Posterior Pelvic Pain Provocation (P4) test: You lie on your back with one hip flexed to 90 degrees. The examiner presses down through your femur. A positive test reproduces your familiar posterior pelvic pain. The P4 test has a sensitivity of 81% and a specificity of 80% for diagnosing pregnancy-related PGP.
• Active Straight Leg Raise (ASLR) test: You lie flat and lift one leg 20 cm off the table without bending the knee. If this reproduces pain or feels noticeably harder on one side, it suggests impaired load transfer through the pelvis.
• Patrick's FABER test: The examiner flexes, abducts, and externally rotates your hip. Pain in the groin suggests hip joint pathology; pain in the SI area suggests sacroiliac involvement.
• Symphysis palpation: Direct tenderness over the pubic symphysis, felt by pressing gently above the pubic bone, localises pain to the front.

When Imaging Is Needed

Imaging is not required to diagnose PGP, but it is appropriate if:

• Red flags are present (see below)
• You are outside pregnancy and inflammatory arthritis is suspected, in which case MRI of the sacroiliac joints without gadolinium is the preferred modality
• A stress fracture of the pubic rami is possible after trauma or in women with low bone density

Pelvic X-ray exposes the ovaries to radiation and should be avoided during pregnancy and used thoughtfully at any reproductive age.

When Should You Worry About Pelvic Girdle Pain?

Most PGP is benign and musculoskeletal. Several features warrant urgent or expedited evaluation.

Seek same-day or emergency care if you have:

• Numbness, tingling, or weakness in your legs alongside pelvic pain (possible cauda equina syndrome or nerve root compression)
• Loss of bladder or bowel control
• Pelvic pain with fever and vaginal discharge (possible pelvic inflammatory disease or septic arthritis)
• Sudden severe pelvic pain in early pregnancy (rule out ectopic pregnancy)

See your clinician within one to two weeks if you have:

• Pain that is worsening despite relative rest and activity modification
• Pain that wakes you from sleep most nights
• Pelvic pain with unexplained weight loss or night sweats (screen for malignancy or inflammatory disease)
• Postpartum pelvic pain that has not improved at all by six weeks after birth

Treatment for Pelvic Girdle Pain

Effective treatment requires matching the approach to the cause and your life stage.

Physiotherapy: The First-Line Approach

A pelvic-floor physiotherapist with specific training in PGP is the single most evidence-backed resource. Treatment typically includes:

Stabilisation exercises. Strengthening the deep abdominals (transversus abdominis), pelvic floor, and gluteal muscles restores the muscle-generated compression needed for the SI joint to transfer load efficiently. A randomised controlled trial published in BMJ found that specific stabilising exercises and acupuncture were both significantly more effective than standard treatment alone for pregnancy-related pelvic pain, with the exercise group reporting the greatest reduction in sick leave.

Manual therapy. Gentle sacroiliac joint mobilisation and soft-tissue work can reduce pain and improve mobility, though manipulation (high-velocity thrust) is approached with caution during pregnancy.

Education and load management. Learning which movements aggravate your specific joint pattern, and temporarily modifying them, reduces cumulative micro-stress. This is not about stopping all activity; it is about pacing.

Pelvic Support Belts

A rigid or semi-rigid pelvic belt worn below the anterior superior iliac spines can reduce SI joint laxity during walking. A biomechanical study using kinematic analysis showed that trochanteric belts measurably reduce SI joint laxity in women with pregnancy-related PGP. They are not a cure, but many women find them helpful for specific activities like grocery shopping or prolonged standing.

Pain Relief by Life Stage

During pregnancy:

• Paracetamol (acetaminophen) at the lowest effective dose for the shortest necessary duration is considered first-line for acute pain. The FDA's 2015 drug safety communication notes that while paracetamol is among the most-studied analgesics in pregnancy, prolonged use should be avoided.
• NSAIDs such as ibuprofen are contraindicated from 20 weeks gestation onward due to risk of fetal renal dysfunction and premature closure of the ductus arteriosus, per ACOG guidance.
• Opioids carry risks of neonatal opioid withdrawal syndrome and should be avoided unless no alternatives exist.

Postpartum and breastfeeding:

• Ibuprofen is considered compatible with breastfeeding at standard doses; the LactMed database confirms that infant exposure through breast milk is very low, typically less than 0.6% of the maternal weight-adjusted dose.
• Naproxen transfers slightly more into breast milk than ibuprofen and is a second choice.
• Paracetamol remains safe during lactation.

Outside pregnancy:

• NSAIDs are appropriate for short-term acute pain management.
• For women with suspected axial spondyloarthritis, early referral to rheumatology and consideration of biologic therapy (TNF inhibitors) may be warranted. Several TNF inhibitors are considered relatively safe through the second trimester for women who wish to conceive, though all should be discussed with a specialist.
• Perimenopause-related PGP may improve with systemic hormone therapy in women who are also symptomatic from other menopausal symptoms, through estrogen's effect on collagen and connective tissue. The Menopause Society 2023 position statement supports hormone therapy for appropriate candidates and notes musculoskeletal benefits as an emerging area of evidence.

Injections

Imaging-guided corticosteroid injections into the sacroiliac joint may provide several weeks of relief when physiotherapy alone is insufficient. They are avoided during pregnancy and used sparingly in women of reproductive age because repeated corticosteroid exposure affects bone density, a particular concern given that young women are still accruing peak bone mass until their early 30s.

Acupuncture

The BMJ RCT cited above also found that acupuncture reduced evening pain scores in pregnant women significantly more than standard treatment, with a mean difference of 0.72 on a 10-point scale. Acupuncture carries a low risk profile in pregnancy when performed by a trained practitioner and is endorsed as an adjunct by several European midwifery guidelines.

PGP Across Life Stages: A Quick Reference

Reproductive Years (Not Pregnant)

Cyclic worsening of SI joint pain in the luteal phase suggests relaxin fluctuation or hypermobility as the driver. Keep a symptom diary tied to your cycle for two to three months. If pain is worst at days 22-28, discuss hypermobility screening with your clinician.

Trying to Conceive

If you have active PGP and are planning pregnancy, starting a pelvic floor and glute strengthening programme before conception significantly reduces the severity of pregnancy-related PGP. A 2016 Norwegian cohort study found that women who exercised regularly before pregnancy had lower rates of severe PGP during pregnancy.

Pregnancy

Onset most commonly between weeks 18 and 36. Symphysis pubis dysfunction can begin as early as the first trimester. The goal is function preservation, not cure, until after delivery. Most women can continue modified low-impact exercise, swimming, and water aerobics, which reduce joint load.

Postpartum

The first six weeks are often the most symptomatic because relaxin remains elevated during breastfeeding. Serum relaxin concentrations in breastfeeding women are measurably higher than in non-breastfeeding postpartum women, which may delay ligament restiffening. Introduce load-bearing exercise gradually, beginning with pelvic floor activation and progressing to bridging and clamshells before returning to running.

Perimenopause and Menopause

The combination of declining estrogen, loss of muscle mass, and cumulative joint wear creates a distinct PGP phenotype in women aged 45 and older. These women are more likely to have an inflammatory or structural component than pregnant women, and imaging is more frequently indicated. Bone density screening with DXA is worth discussing, particularly if pain has been severe enough to restrict load-bearing activity for months.

Who Is Most Likely to Benefit from Each Treatment

| Profile | Recommended starting point | |---|---| | Pregnant, mild PGP, first episode | Pelvic physio, pelvic belt for loading activities | | Pregnant, moderate-severe PGP | Pelvic physio plus acupuncture, crutches if needed | | Postpartum, not resolved at 6 weeks | Pelvic physio, ibuprofen short-term, reassess at 12 weeks | | Non-pregnant, cyclic PGP | Symptom diary, hypermobility screen, pelvic physio | | Non-pregnant, morning stiffness, age <45 | Rule out axSpA with MRI SI joints and HLA-B27 | | Perimenopause, new-onset joint pain | Rule out arthritis, consider HRT if other menopause symptoms present | | Chronic PGP (>12 months) | Multidisciplinary pain programme, psychology referral if central sensitisation suspected |

What Helps Day to Day

These practical adjustments are not substitutes for professional care, but they reduce daily pain load:

• Sleep with a pillow between your knees. This prevents internal rotation of the hip and reduces SI joint stress overnight.
• Sit symmetrically. Avoid crossing your legs or sitting with your weight shifted to one buttock.
• Get out of the car by swivelling both legs together, not stepping out one leg at a time.
• Avoid single-leg activities that are not part of your rehabilitation programme, including standing on one leg to dress.
• Reduce stride length when walking to lower the rotational stress on the SI joint.
• Use a step stool to avoid wide-leg movements when climbing.

Pregnancy, Postpartum, and Contraception Considerations

This section is specifically for women using any pharmacological treatment for PGP.

Paracetamol in pregnancy: Consider first-line for acute pain. Avoid continuous daily use beyond two weeks; a 2021 consensus statement signed by 91 scientists and clinicians in Nature Reviews Endocrinology warned that prolonged prenatal paracetamol exposure is associated with a small but statistically significant increase in risk of neurodevelopmental and reproductive outcomes in offspring. The current guidance is to use the lowest effective dose for the shortest time.

NSAIDs in pregnancy: Avoid from 20 weeks. Before 20 weeks, use only if clearly needed, as some data suggest an association with early miscarriage with prolonged use.

Muscle relaxants (e.g., cyclobenzaprine): Not recommended during pregnancy. Limited lactation data; avoid if alternatives exist.

Corticosteroid injections: Avoid during pregnancy unless pain is severely debilitating and non-pharmacological options have been exhausted. A single SI joint injection carries a low systemic fetal dose but is not a routine option.

Contraception note: If you are taking prescription NSAIDs or corticosteroids long-term for inflammatory PGP and you do not want to become pregnant, use reliable contraception. NSAIDs may reduce the efficacy of an IUD by theoretically inhibiting prostaglandin-mediated implantation, though this interaction is debated; discuss with your clinician.