Hematologic Changes in Pregnancy

Blood volume expansion:- Plasma volume: ↑ 50% (by 32–34 weeks) - RBC mass: ↑ 20–30% - Plasma increases disproportionately → dilution of RBC → physiological (dilutional) anemia - Normal Hgb in pregnancy: ≥11 g/dL (1st/3rd trimester); ≥10.5 g/dL (2nd trimester) - Iron deficiency anemia (IDA) defined at Hgb <11/10.5 g/dL Leukocytes (WBC): - WBC increases to 5,000–15,000/mm³ (normal in pregnancy) - Can increase further in labor to 25,000–30,000/mm³ (physiological stress response) - Interpretation: a WBC of 15,000 in a laboring client is NOT necessarily infection Platelets: - May decrease slightly (gestational thrombocytopenia — benign, no fetal effects) - Platelet count 80,000–150,000 in pregnancy: monitor; if associated with hypertension = HELLP - Platelet count <100,000: assess for HELLP, ITP, TTP Coagulation factors (hypercoagulable state): - Fibrinogen: doubles (from 200–400 → 400–600 mg/dL) - Factors VII, VIII, X, XII: increase - Factors XI, XIII: decrease slightly - Protein S: decreases (natural anticoagulant) - NET EFFECT: hypercoagulable state — protective against hemorrhage at delivery, but increases VTE risk DVT/PE risk in pregnancy: - 5× higher risk than non-pregnant women of same age...