An understanding of normal maternal-fetal physiology is critical in the diagnosis, surgical management, and postoperative care of pregnant women who require major surgery or who have been injured. Normal clinical and laboratory findings among pregnant women would suggest disease among women who were not pregnant. The differentiation between normal physiology and disease in these groups of women will save them from exposure to needless, and sometimes dangerous, diagnostic testing. Table 2 outlines the differences in laboratory values between pregnant and nonpregnant women.Table 2. Laboratory Values in PregnancyValueNonpregnantPregnantElectrolytes and acid-base valuesSodium (mEq/L)135–145132–140Potassium (mEq/L)3.5–5.03.5–4.5Chloride (m/Eq/L)100–10690–105Bicarbonate (mEq/L)24–3017–22Pco2(mmHg)35–5025–30 Po2 (mmHg)98–100101–104 Base excess (mEq/L)0.73–4Arterial pH7.38–7.447.40–7.45BUN (mg/dL)10–184–12Creatinine (mg/dL)0.6–1.20.4–0.9 Creatinine clearance (mL/min)3.5–5.02.0–3.7 Osmolality (...
