Association of Progestogens and Venous Thromboembolism Among Women of Reproductive Age.

Objective: To evaluate associations between use of seven progestogens and incident acute venous thromboembolism (VTE) among women of reproductive age.

Methods: This nested matched case-control study identified women aged 15-49 years from January 1, 2010, through October 8, 2018, in the IBM MarketScan databases, a nationwide sample of private insurance claims in the United States. After exclusions, 21,405 women with incident acute VTE (case group), identified by diagnosis codes, were matched 1:5 by year of birth and index date through risk set sampling to 107,025 women without prior VTE (control group). From lowest to highest systemic dose based on a modified hierarchy, progestogens studied were levonorgestrel-releasing intrauterine device (LNG-IUD), oral norethindrone, etonogestrel implant, oral progesterone, oral medroxyprogesterone acetate, oral norethindrone acetate, and depot medroxyprogesterone acetate (DMPA). Conditional logistic regression models adjusted for 16 VTE risk factors were used to estimate odds ratios and 99% CIs for incident acute VTE associated with current progestogen use compared with nonuse. The primary analysis treated each progestogen as a binary exposure. Dose, which varied for oral formulations, and chronicity were explored separately. Significance was set at P <.01 to allow for multiple comparisons.

Results: Current use of higher-dose progestogens was significantly associated with increased odds of VTE compared with nonuse (oral norethindrone acetate: adjusted odds ratio [aOR] 3.00, 99% CI 1.96-4.59; DMPA: aOR 2.37, 99% CI 1.95-2.88; and oral medroxyprogesterone acetate: aOR 1.98, 99% CI 1.41-2.80). Current use of other progestogens was not significantly different from nonuse (LNG-IUD, etonogestrel implant, and oral progesterone) or had reduced odds of VTE (oral norethindrone). Sensitivity analyses that assessed misclassification bias supported the primary findings.

Conclusion: Among reproductive-aged women using one of seven progestogens, only use of norethindrone acetate and medroxyprogesterone acetate-considered higher-dose progestogens-was significantly associated with increased odds of incident acute VTE. The roles of progestogen type, dose, and indication for use warrant further study.