Which of the following groups is at the highest risk for VTE when using hormonal contraceptives postpartum?

The group that is at the highest risk for venous thromboembolism (VTE) when using hormonal contraceptives postpartum is women who smoke and are 35 years or older. This demographic faces an increased risk due to the combined effects of age, smoking, and the influence of hormonal contraceptives on the coagulation system.

As women age, especially after 35, the risk for VTE increases due to age-related changes in vascular and clotting factors. Smoking further exacerbates this risk because it is a known contributor to endothelial damage and increased thrombus formation. The interaction of these risk factors alongside the procoagulant effects of hormonal contraceptives can lead to a significantly heightened risk of developing VTE.

In contrast, women under 21 generally have a lower incidence of VTE associated with hormonal contraceptive use. Breastfeeding does not inherently place women at a higher risk for VTE; in fact, it has protective factors against it due to changes in metabolism and hormonal balance. Women with a BMI below 25 typically have a lower risk profile for VTE, as obesity is a well-known risk factor for thrombotic events. Thus, the combination of being older and a smoker is indeed the most concerning in this context