Factor VII (plasma)
Factor VII is a vitamin K–dependent coagulation factor that initiates the extrinsic pathway. It rises substantially during pregnancy and contributes to the hypercoagulable state of gestation.
| Units | Nonpregnant Adult | 1st Trimester | 2nd Trimester | 3rd Trimester |
|---|---|---|---|---|
| % | 50 – 150 | 100 – 146 | 95 – 153 | 149 – 211 |
Pregnancy physiology
- Factor VII rises progressively across gestation under estrogen influence.
- This contributes to the physiologic prothrombotic state of pregnancy.
- Levels peak in the third trimester.
Causes of elevated Factor VII
- Normal pregnancy physiology (most common)
- Inflammation or infection
- High-estrogen states (IVF stimulation, estrogen therapy)
- Chronic inflammatory disease
- Liver regeneration after injury
Marked elevation may amplify venous thromboembolism risk when combined with inherited or acquired thrombophilias.
Causes of low Factor VII
- Congenital Factor VII deficiency
- Liver disease (cirrhosis, acute hepatitis)
- Vitamin K deficiency or warfarin exposure
- Disseminated intravascular coagulation (DIC)
- Massive transfusion (dilutional)
Factor VII has the shortest half-life of all clotting factors and declines early in liver dysfunction or vitamin K deficiency.
Clinical interpretation & pregnancy considerations
- Factor VII normally rises significantly in pregnancy, especially in the third trimester.
- Low levels may predispose to mucosal bleeding and postpartum hemorrhage.
- In suspected liver disease, assess with INR, fibrinogen, Factor V, and platelet count.
- Congenital Factor VII deficiency may require recombinant FVIIa for delivery planning.
- Marked elevation alone is usually not pathologic but contributes to thrombotic risk.
References
- Abbassi-Ghanavati M, Greer LG, Cunningham FG. Pregnancy and laboratory studies: a reference table for clinicians. Obstet Gynecol. 2009;114:1326–31.