Is a pulmonary embolism (PE) or a deep vein thrombosis (DVT) more likely in a patient using an estrogen contraceptive?

Deep Vein Thrombosis vs. Pulmonary Embolism Risk with Estrogen Contraceptives

Deep vein thrombosis (DVT) is more likely to occur than pulmonary embolism (PE) in patients using estrogen-containing contraceptives, as DVT typically precedes PE in the pathophysiological progression of venous thromboembolism (VTE). 1

Risk of VTE with Estrogen Contraceptives

• Combined oral contraceptives (containing both estrogen and progestogen) increase VTE risk approximately two- to six-fold over baseline 1, 2
• Contraceptive use is the most frequent VTE risk factor in women of reproductive age 1
• The absolute risk of VTE remains relatively low in most of the >100 million combined oral contraceptive users worldwide 1
• The risk of thromboembolic disease associated with oral contraceptives disappears after pill use is stopped 2

Pathophysiological Relationship Between DVT and PE

• PE is usually associated with DVT and is rarely unprovoked 1
• PE occurs when a thrombus (blood clot) that forms in the deep veins (DVT), typically in the legs, breaks off and travels to the pulmonary arteries 1
• PE interferes with both circulation and gas exchange, with right ventricular failure due to acute pressure overload being the primary cause of death in severe PE 1

Factors Affecting VTE Risk with Estrogen Contraceptives

• Third-generation combined oral contraceptives (containing progestogens like desogestrel or gestodene) are associated with higher VTE risk than second-generation contraceptives (containing progestogens like levonorgestrel or norgestrel) 1, 3
• The risk of thromboembolic complications increases two- to four-fold in the post-operative period with oral contraceptive use 2
• Women with predisposing conditions have twice the risk of venous thrombosis compared to women without such conditions 2
• Severe inherited thrombophilia significantly increases the risk of VTE in women using estrogen contraceptives 1, 4

Safer Contraceptive Alternatives

• Hormone-releasing intrauterine devices and some progesterone-only pills (used at contraceptive doses) are not associated with a significant increase in VTE risk 1, 4
• These safer alternatives are often recommended for women with a personal or strong family history of VTE 1

Clinical Management Considerations

• Oral contraceptives should be discontinued at least four weeks prior to and for two weeks after elective surgery associated with increased thromboembolism risk 2
• Oral contraceptives should not be started earlier than four weeks after delivery in women who elect not to breastfeed, as the immediate postpartum period is associated with increased thromboembolism risk 2
• Women at high risk for thrombosis need careful evaluation and counseling for contraception to lower the risk of thrombosis 5
• Women who develop hormone-associated VTE are generally advised to discontinue oral contraceptive use 4

Common Pitfalls and Caveats

• The risk of VTE is highest during the first few months of oral contraceptive use 5
• Even a single high-dose exogenous estrogen intake may induce pulmonary thromboembolism in susceptible individuals 6
• The presence of other cardiovascular risk factors (smoking, obesity, hypertension) can compound the VTE risk associated with oral contraceptives 2
• Healthcare providers should carefully assess VTE risk factors before prescribing estrogen-containing contraceptives, particularly in women with a personal or family history of VTE 3