COMPLETE BLOOD COUNT (CBC)
Hemoglobin and hematocrit (normal pregnancy hemoglobin 10–12 g/dL):
Although nonpregnancy female hemoglobin reference range is 12–14 g/dL,
normal values in pregnancy will reflect the dilutional effect of greater plasma
volume increase than red blood cell (RBC) mass.
Mean corpuscular volume (MCV): Because hemoglobin and hematocrit
reflect pregnancy dilution, MCV may be the most reliable predictor of true
anemia. A low hemoglobin and low MCV (<80 μm3) most commonly
suggests iron deficiency, but may also be caused by thalassemia. A low
hemoglobin and high MCV (>100) suggests folate deficiency or, rarely,
vitamin B12 deficiency.
Platelet count: A low platelet count (<150,000/mm3) is most likely indicative
of gestational (pregnancy-induced) thrombocytopenia. Preeclampsia with
severe features and idiopathic thrombocytopenic purpura (ITP) are
uncommon causes of low platelets. Disseminated intravascular coagulation is
rare.
Leukocyte count (normal pregnancy white blood cell count in pregnancy is
up to 16,000/mm3): Leukopenia suggests immune suppression or leukemia.