What is the recommended Venous Thromboembolism (VTE) prophylaxis for a 45-year-old pregnant woman at 35 weeks gestational age, with a Body Mass Index (BMI) of 31, scheduled for a Cesarean Section (C/S) and taking pregnancy vitamins?

VTE Prophylaxis for Cesarean Section in a 45-Year-Old Woman with BMI 31

This patient requires both enoxaparin and compression devices (Answer A). She has two minor risk factors—advanced maternal age (45 years) and Class I obesity (BMI 31)—which together with cesarean delivery warrant combined mechanical and pharmacologic prophylaxis.1, 2

Risk Stratification

This patient meets criteria for pharmacologic prophylaxis based on multiple risk factors:

• Advanced maternal age (45 years) constitutes a minor risk factor for VTE 2, 3
• Class I obesity (BMI 31) represents an additional minor risk factor 2, 3
• Cesarean delivery inherently increases VTE risk compared to vaginal delivery 2
• The American College of Chest Physicians (ACCP) guidelines specify that the presence of at least two minor risk factors indicates a VTE risk above 3%, warranting pharmacologic thromboprophylaxis 2

Recommended Prophylaxis Strategy

All women undergoing cesarean delivery must receive sequential compression devices starting before surgery and continuing until fully ambulatory (GRADE 1C recommendation). 1, 2, 3 This applies universally regardless of additional risk factors.

For women at increased risk due to at least two minor risk factors, pharmacologic thromboprophylaxis with prophylactic low-molecular-weight heparin (LMWH) should be added while in hospital following delivery (Grade 2B). 1, 2

Specific Prophylaxis Protocol

Enoxaparin is the preferred thromboprophylactic agent in pregnancy and the postpartum period (GRADE 1C): 1, 2, 3

• Standard prophylactic dose: Enoxaparin 40 mg subcutaneously once daily 2, 3, 4
• Initiate postoperatively, typically 6-12 hours after cesarean section when bleeding risk is acceptable 5
• Continue compression devices until the patient is fully ambulatory 1, 2, 3

Note: For Class III obesity (BMI ≥40), intermediate doses of enoxaparin would be considered, but this patient's BMI of 31 does not meet that threshold. 1, 2

Duration of Prophylaxis

Mechanical prophylaxis should continue until full ambulation. 1, 2, 3

Pharmacologic prophylaxis duration depends on persistent risk factors: 1, 2

• Minimum duration: At least 10 days postpartum for patients with intermediate risk 3, 5
• Extended prophylaxis up to 6 weeks after delivery should be considered if risk factors persist postpartum (Grade 2C) 1, 2

Why Other Options Are Incorrect

Option B (vitamins only) is inadequate: Pregnancy vitamins provide no VTE prophylaxis. This patient has identifiable risk factors requiring intervention. 1, 2

Option C (early ambulation alone) is insufficient: The ACCP specifically recommends against using thrombosis prophylaxis other than early mobilization only for women without additional risk factors (Grade 1B). 1 This patient has two minor risk factors beyond the cesarean delivery itself.

Option D (aspirin) is not indicated: Antiplatelets are not recommended for VTE prophylaxis in the postpartum period. Low-molecular-weight heparin is the evidence-based pharmacologic agent. 1, 2

Common Pitfalls to Avoid

• Do not rely on mechanical prophylaxis alone when two or more minor risk factors are present—pharmacologic prophylaxis is necessary 1, 2
• Do not use unfractionated heparin when LMWH is available, as LMWH is the preferred agent (GRADE 1C) 1, 2
• Do not stop prophylaxis at hospital discharge if risk factors persist—consider extension to 6 weeks postpartum 1, 2
• Do not administer enoxaparin too early postoperatively—allow 6-12 hours after cesarean section to minimize bleeding risk 5