Normal Laboratory Values in Pregnancy
Alanine Aminotransferase (ALT or SGPT)
Increases in HELLP syndrome
Decreases in pregnancy due to hem dilution. Plasma oncotic pressure decreases as well.
Levels increase in pregnancy 11-128 units/L
(peaking in the 3rd trimester. Further increases may be seen when there is liver impairment.
1) Serum amylase rises gradually during pregnancy until the twenty-fifth week and thereafter falls slightly
(2) Serum amylase values in normal pregnant women in the second and third trimesters may exceed those seen in normal men and nonpregnant women
(3) During the second trimester of pregnancy there may be an alteration in the relative distribution of the pancreatic and salivary-type isoamylases with the salivary type tending to dominate. Knowledge of these changes is of importance in the clinical assessment of serum amylase values in pregnant women complaining of abdominal pain and other symptoms suggestive of acute pancreatitis
Arterial Blood Gases
PO2 85-100mmHg 104-108mmHg
PCO[sub]2 35-45mmHg 27-32mmHg
Ph 7.35-7.45 7.35-7.45
SaO[sub]2 95-99% 95-99%
HCO[sub]3 22-28mEq/L 18-25mEq/L.
Please note the decrease in HCO3 values due to renal excretion of bicarbonate (compensatory metabolic acidosis)
Aspartate Aminotransferase (AST or SGOT)
Increases in acute fatty liver of pregnancy, HELLP syndrome and preeclampsia
>11 minutes are of concern
Blood Urea Nitrogen (BUN)
Decreases in pregnancy
BUN levels are normally lower especially towards the end of pregnancy when the fetus is using large amounts of protein.
Serum Ionized 4.0-4.8mg/dL
Total calcium level decreases because of hemodilution. However, ionized Ca remains the same due to decrease in serum albumin.
Complete Blood Count (CBC)
Hgb 12-16g/dL. Pregnancy decreases Hgb by 1.5-2 g.dL
Hct 37-47%. (4-6% decrease in pregnancy)
RBC 4.2-5.4 x 10[sup]6/ul. Pregnancy decreases by 0.8 x 10[sup]6/ul
MCV 81-99 um[sup]3 (81-99fl)
MCH 27-31 pg (27-31pg)
MCHC 33-37 g/dl (330-370 g/L)
WBC 4.8-10.8 X 10[sup]3/ul (4.8-10.8 X 10[sup]9/L); 5-12K in pregnancy and 14-16K during labor.
Segs 53-79%; Bands 1-10 %;Eos 0-4%;Lymphs 13-46%;Monos 3-9%;Basos 0-1%
5-25ug/dl (138-690 nmol/L) in the morning and 3-13ug/dl (83-359 nmol/L in the evening.
Pregnancy 0.4-0.8 mg/dl.
Creatinine > 1 mg/dL signifies renal dysfunction in pregnancy
Chloride 98-109 mEq/L
Potassium 3.5- 5.0 mEq/L
Bicarbonate 18-21 mmol/L
Potassium decreases 0.1-0.2mEq/L and Sodium decreases 2-3 mEq/L
I Fibrinogen Changes in pregnancy 4.0-6.5 g/l
II Prothrombin Changes in pregnancy 100-125%
IV Ca.[sup]++ - No change
V Proaccelerin -.changes in pregnancy100-150%
VII Proconvertin-Changes in pregnancy 150-250%
VIII Antihemophilic Changes in pregnancy200-500%
IX Antihemophilic B (Christmas factor) changes in pregnancy 100-150%
X Stuart- Prower Factor Changes in pregnancy 150-250%
XI Antihemophilic Factor C Changes in pregnancy 50-100%
XII Hageman Factor Changes in pregnancy 100-200%
XIII Fibrin Stabilizing Factor Changes in pregnancy 35-75% Antithrombin III Changes in pregnancy 75-100%
Antifactor Xa Changes in pregnancy 75-100%
Factors XI and XIII decrease in pregnancy. All other factors increase or remain the same.
Erythrocyte Sedimentation Rate (ESR)
<20mm/h. Increases in pregnancy
Fibrin Degradation Products
<10ug/ml. High levels with abruption, fetal demise, and disseminated intravascular coagulations.
Hgb A1C 3.6-4.9%; Hgb A1 5.1-7.8%
Iron binding capacity
Magnesium (You must know what units your laboratory are using, mg/dL, mEq/l or mmol/L)
Note: 2.7 mg/dL=2 mEq/L=1 mmol/L
Slight decrease in pregnancy (10%)
Therapeutic level 4-7mg/dl
Loss of patellar reflex 8-12mg/dl
Feeling of warmth, flushing 9-12mg/dl
Slurred speech 10-12mg/dl
Muscular paralysis 15-17mg/dl
Respiratory difficulty 15-17mg/dl
Cardiac arrest 30-35mg/dl
Parathyroid Hormone (PTH) and Markers of bone turnover
In one study, morning blood and urine samples were obtained for laboratory tests: within 3 months before conception (baseline); between 22 and 24 gestational weeks; after delivery, and 6 and 12 months postpartum. Serum 25-hydroxyvitamin D (25-OH-D), parathyroid hormone, bone specific alkaline phosphates, osteocalcin (OC), procollagen I carboxypeptides, calcium, phosphate and creatinine in addition to urine deoxypyridinoline crosslinks and calcium were measured. There was no significant difference in the values of urinary calcium / creatinine and serum calcium, phosphate and 25-OH-D between the different visits during the study.
Plasma levels of inorganic phosphorus do not change appreciably from nonpregnant levels.
Mild Gestational Thrombocytopenia Plt. Count 100,000-149,000/mm
Moderate Gestational Thrombocytopenia Plt. Count 50,000-99,000/mm
Profound Gestational Thrombocytopenia Plt. Count <50,000
Prothrombin Time (PT)
10.6-12.9 Sec. No significant change in pregnancy
Normal within 5 sec. of control
Tyroxine (T4)5.0 12.6ug/dl
Triiodothyronine (FreeT3) 125-300pg/dl;
Thyroid Stimulating Hormone (TSH) 0.5-3.8 uU/ml
Venous blood was tested for human chronic gonadotropin (hCG), thyroid-stimulating hormone (TSH), free thyroxin (FT4) and total triiodothyronine (TT3). Early pregnancy thyroid function tests showed a significant decrease (p < 0.001) in TSH and a significant increase (p < 0.001) in TT3 as compared to the nonpregnant state; FT4, however, did not change significantly. In 8 (11.2%) pregnant subjects, TT3 levels were above the normal range for nonpregnant controls. Elevated thyroid function in early pregnancy is transient, and does not usually warrant antithyroid treatment. Thus, any conclusion regarding thyroid function in early pregnancy should be based on pregnant controls rather than general population controls.
Adult females: 2.0 - 6.5 mg/dl; in early pregnancy uric acid levels fall by about one-third but rise to non-pregnant levels by term.