Factor VIII (plasma)
Factor VIII is a key coagulation factor deficient in hemophilia A. During pregnancy, levels rise substantially under estrogen influence and contribute significantly to the hypercoagulable state of gestation.
| Units | Nonpregnant Adult | 1st Trimester | 2nd Trimester | 3rd Trimester |
|---|---|---|---|---|
| % | 50 – 150 | 90 – 210 | 97 – 312 | 143 – 353 |
Pregnancy physiology
- Factor VIII rises progressively across gestation under hormonal control.
- The increase is more pronounced than for Factors V and VII.
- Peak levels occur in the late third trimester.
Causes of elevated Factor VIII
- Normal pregnancy physiology (most common)
- Inflammation or infection
- Trauma or surgery
- Obesity
- Independent venous thromboembolism risk factor
Persistently elevated Factor VIII is a well-established independent risk factor for venous thromboembolism.
Causes of low Factor VIII
- Hemophilia A (mild, moderate, or severe)
- von Willebrand disease (types 1, 2N, and 3)
- Disseminated intravascular coagulation (DIC)
- Severe liver disease
- Massive transfusion (dilutional)
Unlike Factor VII, Factor VIII typically rises in liver disease because it is synthesized primarily by endothelial cells.
Clinical interpretation & pregnancy considerations
- Factor VIII rises 3–5× baseline in late pregnancy.
- Mild hemophilia A or VWD may normalize during pregnancy but drop rapidly postpartum.
- Rapid postpartum decline increases postpartum hemorrhage risk.
- Measure levels in hemophilia carriers and VWD patients for delivery planning.
- Neuraxial anesthesia usually requires FVIII ≥ 50–80% depending on institutional policy.
Close postpartum monitoring is essential in inherited bleeding disorders.
References
- Abbassi-Ghanavati M, Greer LG, Cunningham FG. Pregnancy and laboratory studies: a reference table for clinicians. Obstet Gynecol. 2009;114:1326–31.