especially in the third trimester
| Etiology | • Enlarged uterus → exaggerated lordosis • Joint/ligament laxity from ↑ progesterone/relaxin • Weak abdominal muscles → decreased lumbar support | | --- | --- | | Risk factors | • Excessive weight gain • Chronic back pain • Back pain in prior pregnancy • Multiparity | | SOCRATES | • Mechanical back pain (eg, position-dependent, achy, worsened with activity, relieved with rest). • Usually bilateral and no radiation below knee • May be associated with a waddling gait but no neurologic defecits • Numbness in feet, which is present only at the end of the day, is likely related to physiologic ankle edema not related to the pain | | Imaging | • Not indicated | | Management | • Behavioral modifications (eg, wearing supportive shoes, using a firm mattress) and exercise • Heating pads & massage • Analgesics | | Prognosis | • Reassurance that the back pain is normal and will resolve postpartum. |
In contrast, concerning nonmechanical causes of back pain (eg, preterm labor, pyelonephritis, spinal malignancy) may present with fever, neurologic deficits (eg, bowel or bladder incontinence), and constant, nonpositional, nocturnal back pain.
Her back pain is bilateral without radiation below the knee, making lumbosacral radiculopathy (sciatica) unlikely.
<aside> 💡 Prior neuraxial anesthesia does not increase the risk for long-term back pain.
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Epidural corticosteroid injections can provide short-term relief for chronic radicular pain from lumbar disc herniation (ie, unilateral pain radiating below the knee along the sciatic nerve). However, this patient's pain is bilateral and does not radiate below the knee, making this diagnosis unlikely. Epidural injections are not recommended for mechanical back pain.
MRI is the preferred imaging modality for pregnant women with back pain but is usually needed only when there are associated neurologic deficits, features of infection (eg, fever, focal spinal tenderness), or malignancy (eg, unexpected weight loss). Minor pregnancy-related symptoms (eg, urinary frequency, edema) do not require imaging.
Strict bed rest is rarely recommended in pregnancy due to the increased risk for thromboembolism, bone loss, and physical deconditioning, which can exacerbate back pain.
Nonsteroidal anti-inflammatory drugs (eg, ibuprofen, naproxen) are avoided in the first and third trimesters due to risks for renal teratogenicity and premature closure of the ductus arteriosus.