Table 2: Basic laboratory investigations recommended for monitoring patients with hypertension in pregnancy
Laboratory investigation	Grade of recommendation	Rationale
Hemoglobin and hematocrit measurement2,53,54	D	Hemoconcentration supports diagnosis of gestational hypertension with or without proteinuria. It indicates severity. Levels may be low in very severe cases because of hemolysis
Platelet count56-58,62	C	Low levels (< 100 000 X 109/L) may suggest consumption in the microvasculature. Levels correspond to severity and are predictive of recovery rate in postpartum period, especially for women with HELLP syndrome*
Serum aspartate aminotransferase and alanine aminotransferase measurement5,61	C	Elevated levels suggest hepatic involvement. Increasing levels suggest worsening severity
Serum lactate dehydrogenase measurement5,61	C	Elevated levels associated with hemolysis and hepatic involvement. May reflect severity and may predict potential for recovery postpartum, especially for women with HELLP syndrome
Protein level in 24-hour urine collection2,4,10,14	D	Standard to quantitate proteinuria. If in excess of 2 g/d, very close monitoring is warranted. If in excess of 3 g/d, delivery should be considered
Urinalysis14,19,50	A	Dipstick test for proteinuria has significant false- positive and false-negative rates. Results should be interpreted taking into account pH, specific gravity, bacterial or leukocyte count, hemoglobin concentration and red blood cell contamination. If dipstick result is positive ( +1), 24-hour urine collection is needed to confirm proteinuria. Negative dipstick results do not rule out proteinuria, especially if diastolic pressure is greater than 90 mm Hg
Serum uric acid measurement60,72,73	B	Elevated levels aid in differential diagnosis of gestational hypertension and may reflect severity
Serum creatinine measurement74	C	Levels drop in pregnancy. Elevated levels suggest increasing severity of hypertension. assessment of 24-hour creatinine clearance may be necessary. Elevated levels may be within normal limits for nonpregnant people
Fetal assessment		See text for comments
Non-stress test76-79	D
Biophysical profile80,81	C
Fetal movement count75	D
Doppler flow velicitometry82-86	B
*HELLP = Hemolysis, Elevated Liver enzyme levels and Low Platelet count.

[Return to text]