Yes, Depo-Provera Should Count as Hormone Use in PERC
When applying the PERC rule to rule out pulmonary embolism, depot medroxyprogesterone acetate (Depo-Provera) should be counted as hormone use, as it is associated with increased venous thromboembolism risk.
Evidence Supporting VTE Risk with Depo-Provera
The evidence clearly demonstrates that Depo-Provera carries thrombotic risk:
Depot medroxyprogesterone acetate is associated with a 2-3 fold increased risk of venous thromboembolism compared to non-users 1, 2, 3. The French Society of Endocrinology guidelines specifically note that studies show a significant increase in VTE risk with medroxyprogesterone acetate, with one WHO study showing an OR of 2.19 and another demonstrating statistically significant increased risk 1.
A large US case-control study found that DMPA was associated with a 2.37-fold increased odds of VTE (99% CI 1.95-2.88) 2, while another study reported a 3.6-fold increased risk (95% CI 1.8-7.1) 3.
The 2019 ESC Guidelines acknowledge that while progesterone-only pills at contraceptive doses are not associated with significant VTE risk, this reassurance specifically applies to low-dose oral formulations and intrauterine devices 4. The guidelines explicitly distinguish these from other progestin formulations.
Why Depo-Provera is Different from Other Progestin-Only Methods
The critical distinction is dose and formulation:
High-dose progestins like DMPA (150 mg every 3 months) have different pharmacological properties that may explain the increased thrombotic risk 1. The French guidelines note that "the pharmacological properties of this progestin, used at high doses, may explain these results" regarding VTE risk 1.
Low-dose progestin-only pills (levonorgestrel 30 mcg, norethisterone 350 mcg, desogestrel 75 mcg) and levonorgestrel IUDs show no significant increase in VTE risk 1, 4. These are fundamentally different from the depot injection.
Recent research confirms this dose-response relationship, showing that oral norethindrone acetate and medroxyprogesterone acetate (higher-dose progestogens) were significantly associated with increased VTE odds, while LNG-IUD, etonogestrel implant, and oral progesterone were not 2.
Clinical Application to PERC
The PERC rule includes "hormone use" as one of its eight criteria because estrogen-containing contraceptives increase VTE risk. The intent is to identify any hormonal therapy that elevates thrombotic risk. Given that:
- Depo-Provera increases VTE risk by 2-4 fold
- This risk is comparable to or exceeds that of some combined oral contraceptives
- The PERC rule aims to identify patients at increased baseline VTE risk
Depo-Provera use should disqualify a patient from PERC rule application, requiring D-dimer testing or imaging based on clinical probability assessment.
Important Caveats
Not all progestin-only contraceptives carry this risk. Levonorgestrel IUDs, low-dose progestin-only pills, and etonogestrel implants do not significantly increase VTE risk and should NOT count as hormone use for PERC purposes 4, 2.
The timing of exposure matters. Recent case reports document severe VTE complications shortly after Depo-Provera administration 5, suggesting the risk may be highest early in treatment.
Combined oral contraceptives remain the most common VTE risk factor in reproductive-age women 4, but Depo-Provera carries comparable or greater risk and should be treated similarly in risk stratification.