Pregnancy woman is affected by changing of center of mass, which is a critical point in any three-dimensional body on which gravity acts. Gravity is a very important force to consider when dealing with biomechanics. The gravitational force acts on the levers of the body to create torque at various body segments and joints.

○ Center of Gravity

✓ COG shifts upward and forward because of the enlargement of the uterus and breasts

✓ The lumbar and cervical lordosis increase, knee hyperextended

✓ The shoulder girdle and upper back become rounded with scapular protraction and upper extremity internal rotation because of breast enlargement; this postural tendency persists with postpartum positioning for infant care

✓ The suboccipital muscles; moderate forward head posture along with the change in shoulder alignment

✓ Weight shifts toward the heels to bring COG to a more posterior position; this contributes to the “waddling” gait that is typical seen in pregnancy

○ Balance

✓ Walks with a wider base of support and increased external rotation at the hips



 Postural back pain

SI/pelvic girdle pain Joint laxity

Nerve compression syndromes


postural changes, increased ligament laxity and decreased abdominal m. function

lower back exercises, proper body mechanics, good posture, superficial modality

✓contraindication during pregnancy: deep-heating agents, EST (except TENS) and traction


✓ SI pain can be radiating to posterior thigh or knee but not into the foot.

✓Pubic symphysis dysfunction can be radiating to the groin and medial thigh. Wt-bearing pain


✓activity modification: minimize asymmetrical forces

✓exercise modification: avoid single-leg wt-bearing and excessive hip abd or hypertext.

✓External stabilization: belts or corsets


✓During pregnancy and during the immediate postpartum period (3-5 mon. after delivery)

✓Aggravates by menstrual cycle


✓Exercise modification: less stressful exercise on joints

✓Aerobic exercise: non-wt bearing (swimming, walking or biking etc)


✓TOS or CTS, LE nerve compression syndromes


✓postural correction exercises, manual therapy, ergonomic assessment, modalities, splints for CTS