That waddling gait and low back pain aren't just discomfort — they signal hormonal remodeling of the entire musculoskeletal system that can mimic pathology if you don't recognize it as normal.
Relaxin and progesterone loosen ligaments and increase connective tissue laxity throughout pregnancy, most notably at the symphysis pubis and sacroiliac joints. This increased joint mobility, combined with the shifting center of gravity as the uterus enlarges, produces progressive lordosis (exaggerated lumbar curve), a wide-based waddling gait, and round ligament pain — sharp, unilateral lower abdominal twinges triggered by sudden movement, typically peaking in the second trimester as the uterus rises out of the pelvis. Normal pregnancy back pain is postural, bilateral, and relieved by position change; back pain that is rhythmic, radiating, and unrelieved by repositioning suggests preterm labor, while unilateral flank pain with fever points to pyelonephritis. Diastasis recti, a midline separation of the rectus abdominis muscles, can appear in the third trimester and is assessed by having the client do a partial sit-up while you palpate at, above, and below the umbilicus — a gap ≥2 fingerbreadths is clinically significant. Other expected changes include hyperpigmentation (melasma, linea nigra) driven by MSH and estrogen effects on melanocytes, striae gravidarum, increased skin vascularity (spider angiomas, palmar erythema), and nasal congestion from estrogen-induced mucosal edema. Mild dependent edema in the lower extremities is normal in late pregnancy; however, facial or upper extremity edema is NOT normal and warrants assessment for preeclampsia. Carpal tunnel symptoms (numbness, tingling in the hands) can develop from fluid retention compressing the median nerve and typically resolve postpartum.
Key Distinctions
Don't confuse normal round ligament pain (sharp, brief, movement-triggered, unilateral lower abdomen) with ectopic pregnancy pain (persistent, often with vaginal bleeding and hemodynamic instability). Students mix up normal dependent ankle edema (gravity-related, bilateral, worsens with standing) with pathological facial/hand edema that signals preeclampsia. Diastasis recti is assessed during a partial sit-up, not at rest — palpating a relaxed abdomen misses the separation. Normal pregnancy back pain (postural, bilateral, position-responsive) differs from preterm labor back pain (rhythmic, radiating, not relieved by repositioning) and pyelonephritis (unilateral flank pain with fever).
Clinical Pearl
Sharp pain with a quick turn? That's round ligament pain — side-lying with pillow support and slow position changes fix it. Swelling in the face? That's never round ligament anything — think preeclampsia.