What VTE prophylaxis is recommended for a 35-week gestational age pregnant woman with a BMI of 31, scheduled for C/S, and no history of DVT or coagulopathy?

VTE Prophylaxis for Cesarean Section at 35 Weeks with BMI 31

This patient requires enoxaparin 40 mg subcutaneously once daily combined with sequential compression devices (Answer A), based on the presence of two minor risk factors: obesity (BMI 31) and cesarean delivery. 1

Risk Stratification

This patient meets criteria for pharmacologic thromboprophylaxis based on the following:

• BMI 31 (Class I obesity) represents a minor risk factor for VTE, with an absolute risk of approximately 1% in isolation 2, 1
• Cesarean delivery inherently increases VTE risk compared to vaginal delivery and constitutes an additional risk factor 1
• 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 1

Recommended Prophylaxis Strategy

Mechanical Prophylaxis

• Sequential compression devices must be applied before surgery and continued until the patient is fully ambulatory (GRADE 1C recommendation) 1
• This recommendation applies to all women undergoing cesarean delivery regardless of risk factors, per ACOG and SMFM guidelines 1

Pharmacologic Prophylaxis

• Enoxaparin 40 mg subcutaneously once daily is the standard prophylactic dose for patients with intermediate risk (at least two minor risk factors) 1
• Low-molecular-weight heparin (enoxaparin) is the preferred thromboprophylactic agent in pregnancy and the postpartum period (GRADE 1C) 1
• Pharmacologic prophylaxis should be initiated postoperatively, typically 6-12 hours after cesarean delivery when hemostasis is assured 3

Duration of Prophylaxis

• Mechanical prophylaxis continues until the patient is fully ambulatory 1
• Pharmacologic prophylaxis should be given for at least 10 days postpartum for intermediate-risk patients 3
• Extension up to 6 weeks may be considered if additional risk factors persist postpartum (Grade 2C) 1

Why Other Options Are Incorrect

Option B (Continue vitamins, no prophylaxis)

• This is inadequate for a patient with two identifiable risk factors (BMI 31 + cesarean delivery) 1
• Pregnancy vitamins have no role in VTE prophylaxis 2
• The ACCP explicitly recommends against withholding prophylaxis when VTE risk exceeds 3% 1

Option C (Early ambulation alone)

• Early mobilization alone is only sufficient for low-risk cesarean patients without additional risk factors (Grade 1B) 1
• This patient has two minor risk factors (obesity + cesarean delivery), placing her in the intermediate-risk category requiring pharmacologic prophylaxis 1

Option D (Aspirin)

• Aspirin is insufficient for VTE prophylaxis in patients with identifiable risk factors 4
• Antiplatelet agents do not provide adequate protection against venous thromboembolism 4
• LMWH is the evidence-based agent of choice for VTE prophylaxis in pregnancy and postpartum 1, 5

Important Clinical Considerations

Dosing Adjustment for Higher BMI Classes

• The standard dose of enoxaparin 40 mg once daily is appropriate for BMI 31 (Class I obesity) 1
• For Class III obesity (BMI ≥40), intermediate doses of enoxaparin 40 mg every 12 hours should be used (GRADE 2C) 1

Contraindications to Monitor

• Enoxaparin is contraindicated if creatinine clearance <30 mL/min; use unfractionated heparin instead 1
• Ensure at least 12-24 hours have elapsed since neuraxial anesthesia before initiating prophylactic LMWH 3

Common Pitfalls to Avoid

• Do not use standard prophylactic dosing in patients with BMI ≥40—this results in subtherapeutic anti-Xa levels 1
• Do not use direct oral anticoagulants (DOACs) in the postpartum period—insufficient safety data exists for apixaban, rivaroxaban, or dabigatran 1
• Do not initiate LMWH before adequate time has elapsed post-neuraxial block to avoid spinal hematoma risk 1