2.6 Musculoskeletal, Vascular & Neurologic Discomforts of Pregnancy

Musculoskeletal Adaptations & Pelvic Girdle Pain

Maternal circulating relaxin and progesterone promote systemic connective tissue remodeling, causing ligamentous laxity in the pubic symphysis and sacroiliac joints. Concurrently, the enlarging uterus shifts the maternal center of gravity anteriorly, inducing compensatory exaggerated lumbar lordosis, anterior pelvic tilt, and thoracic kyphosis.

Round Ligament Pain

• Anatomy & Mechanism: The round ligaments are fibromuscular cords originating at the uterine cornua, traversing the inguinal canals, and inserting into the labia majora. As the uterus enlarges and dextrorotates, these ligaments stretch under tension. Sudden movements, position changes, or coughing produce acute ligamentous spasm.
• Clinical Presentation: Sharp, lancinating, knife-like pain or a dull ache localized to the lower quadrants and groin, frequently worse on the right side (due to physiologic uterine dextrorotation). It is brief, episodic, and positional.
• Differentiating from Surgical Abdomen (Appendicitis, Cholecystitis):

Pelvic Girdle Pain (PGP) & Symphysis Pubis Dysfunction (SPD)

• Etiology: Pathologic relaxation and instability of the pelvic ring. Physiologic widening of the pubic symphysis averages 3–7 mm; separation >10 mm is classified as diastasis of the pubic symphysis.
• Clinical Features: Exquisite pain directly over the pubic symphysis and sacroiliac joints, radiating down the inner thighs. Characterized by a "waddling" gait, audible clicking/popping when walking, and severe pain during unilateral weight-bearing activities (ascending stairs, standing on one leg to don pants, or getting in and out of an automobile).
• Midwifery Interventions:
  • Provide an adjustable maternity support belt / trochanteric binder to mechanically stabilize the pelvic ring.
  • Counsel the patient to perform activities with bilateral symmetrical pelvic loading: sit down to dress, keep knees together when rolling over in bed ("log-rolling"), and avoid straddle positions or deep lunges.
  • Recommend non-weight-bearing aerobic exercise (swimming/water aerobics) and referral to a specialized pelvic floor physical therapist.

Lower Back Pain & Sciatica

• Etiology: Lumbar paraspinal muscle fatigue from altered center of gravity; direct compression of the lumbosacral nerve plexus (L4–S3) by the fetal head or piriformis spasm.
• Management: Proper ergonomic body mechanics (bend at knees, not waist); avoid unsupportive footwear and high heels; firm mattress; localized heat or cold packs; prenatal yoga; acupuncture; acetaminophen (first-line analgesic).
• Caution: Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) such as ibuprofen are contraindicated in the third trimester (≥20–28 weeks) due to premature constriction of the fetal ductus arteriosus and fetal renal impairment resulting in oligohydramnios.

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Vascular, Fluid Balance & Neurological Discomforts

Lower Extremity Edema Differential
├── Dependent (Physiologic) Edema
│   ├── Pathophysiology: IVC compression by gravid uterus -> elevated venous hydrostatic pressure
│   ├── Clinical Signs: Bilateral, symmetric, pretibial/ankle swelling; worse at end of day
│   └── Management: Elevate legs above heart level, lateral recumbency, compression stockings
└── Non-Dependent (Pathologic) Edema
    ├── Pathophysiology: Systemic endothelial activation, vascular permeability, protein leakage
    ├── Clinical Signs: Sudden rapid swelling of face, periorbital tissue, hands; weight gain >1 lb/wk
    └── Management: Immediate BP evaluation, urine protein-to-creatinine ratio, preeclampsia lab panel

Dependent Edema vs. Pathologic Edema

• Physiologic Dependent Edema: Affects up to 80% of healthy pregnant women in the third trimester. Results from mechanical compression of the inferior vena cava and common iliac veins by the gravid uterus, which elevates venous hydrostatic pressure in the lower extremities, coupled with a physiological fall in plasma colloid oncotic pressure. It is bilateral, gravity-dependent (worse in late afternoon), and completely resolves after overnight elevation or left lateral recumbency.
• Pathologic Edema (Preeclampsia Red Flag): Characterized by sudden, rapid swelling of the face, hands (inability to remove rings), and periorbital regions, accompanied by acute weight gain (>1–2 lbs in a week). This mandates immediate evaluation of blood pressure, deep tendon reflexes, and screening for proteinuria.

Lower Extremity and Vulvar Varicosities

• Etiology: High venous pressure and estrogen-mediated vessel wall dilation.
• Management: Prescription graduated compression stockings (20–30 mmHg), donned early in the morning before arising from bed; frequent rest periods with lower extremities elevated above heart level; avoid prolonged upright standing or seated immobility; pelvic compression garments for vulvar varicosities.

Maternal Sleep Disturbances & Vena Cava Compression

• Supine Hypotensive Syndrome: In the supine position after 20 weeks gestation, the heavy gravid uterus compresses both the inferior vena cava and aorta (aortocaval compression), reducing venous return to the heart by up to 25–30%. This precipitates a sharp drop in maternal cardiac output, causing maternal dizziness, pallor, diaphoresis, nausea, and profound uteroplacental hypoperfusion with fetal bradycardia.
• Midwifery Recommendation: Instruct all pregnant patients to adopt a left or right lateral recumbent tilt when resting or sleeping. A wedge pillow placed under the right hip or between the knees maintains optimal pelvic alignment and relieves great vessel compression.

Carpal Tunnel Syndrome (CTS)

• Etiology: Fluid retention and hormone-induced soft tissue edema cause increased compartmental pressure within the inextensible fibro-osseous carpal tunnel, compressing the median nerve.
• Clinical Presentation: Pain, burning, numbness, and paresthesias in the thumb, index finger, middle finger, and radial half of the ring finger. Symptoms are markedly worse at night, often waking the patient from sleep with a desire to "shake out" the hands. Positive Phalen's maneuver and Tinel's sign.
• Midwifery Management:
  • Prescribe rigid neutral wrist splints to be worn overnight (prevents nocturnal wrist flexion that exacerbates median nerve compression).
  • Fluid mobilization through elevation of the upper extremities.
  • Provide reassurance that symptoms resolve spontaneously in over 90% of individuals within 2 to 6 weeks postpartum as pregnancy-associated tissue edema diureses.

Nocturnal Leg Cramps

• Etiology: Involuntary, excruciating spasms of the gastrocnemius muscles, occurring almost exclusively during sleep in the second and third trimesters. Etiological factors include altered calcium-phosphorus homeostasis, intracellular magnesium depletion, and lactic acid buildup secondary to daytime venous stasis.
• Midwifery Interventions:
  1. Immediate Acute Intervention: Teach the patient and partner to perform active, vigorous dorsiflexion of the foot (pulling the toes upward toward the shin) while keeping the knee fully extended. This stretches the contracted gastrocnemius muscle and breaks the spinal reflex arc.
  2. Prophylactic Care: Daily passive calf stretching before retiring to bed; warm baths; adequate hydration.
  3. Oral Pharmacotherapy: Oral magnesium supplementation (e.g., magnesium lactate, magnesium citrate, or magnesium gluconate, 300 to 360 mg daily at bedtime) has demonstrated efficacy in randomized trials for reducing the frequency and severity of nocturnal cramps.