Affected value or system	Change during normal pregnancy
Systolic blood pressure	Decreased by an average of 5 to 15 mm Hg
Diastolic blood pressure	Decreased by 5 to 15 mm Hg
Electrocardiogram	Flat or inverted T waves in leads III, V1, and V2; Q waves in leads III and aVF
Blood volume	Increased by 30 to 50 percent
White blood cell count	May be increased; range: 5,000 to 25,000 per mm3 (5 to 25 × 109 per L; higher in late pregnancy)
Fibrinogen	Increased; range: 264 to 615 mg per dL (2.6 to 6.1 g per L)
D-dimer	Frequently positive
Respiratory rate	Increased by 40 to 50 percent
Oxygen consumption	Increased by 15 to 20 percent at rest
Partial pressure of oxygen	Increased; range: 100 to 108 mm Hg
Partial pressure of carbon dioxide	Decreased; range: 27 to 32 mm Hg
Bicarbonate	Decreased; range: 19 to 25 mEq per L
Base excess	Present; range: 3 to 4 mEq per L
Blood urea nitrogen	Decreased; range: 3 to 3.5 mg per dL (1.1 to 1.2 mmol per L)
Serum creatinine	Decreased; range: 0.6 to 0.7 mg per dL (50 to 60 μmol per L); 1.0 mg per dL [90 μmol per L] may be abnormal
Alkaline phosphatase	Increased because of placental production; range: 60 to 140 IU per L (60 to 140 U per L)
Kidneys	Mild hydronephrosis
Gastrointestinal tract	Decreased gastric emptying, decreased motility, increased risk of aspiration
Musculoskeletal system	Widened symphysis pubis and sacroiliac joints, which may lead to misreading of radiologic studies
Diaphragm	Higher position in pregnancy; consequently, chest tubes would need to be placed one or two interspaces higher.
Peritoneum	Small amounts of intraperitoneal fluid normally present