Increased Risk of Venous Thromboembolism Linked to Specific Hormonal Contraceptives

Research has revealed that the risk of venous thromboembolism (VTE) varies significantly among different hormonal contraceptives. This finding is supported by a recent study published in the Journal of the American Medical Association, which utilized data from Danish national registers to assess VTE risk among women.

In this comprehensive study, researchers examined data from females aged 15 to 49 years, tracking a total of 1,397,235 individuals over a cumulative period of 8,455,601 person-years. The analysis identified 2,691 instances of VTE during the observation period, leading to a detailed comparison of VTE rates across various contraceptive methods.

The standardized VTE rates per 10,000 person-years were reported as follows: 2.0 for nonusers, 10.0 for combined oral contraceptives, 8.0 for vaginal rings, 8.1 for patches, 3.6 for progestin-only pills, 2.1 for intrauterine devices (IUDs), 3.4 for implants, and 11.9 for injections. The study also calculated relative risk ratios for VTE compared to nonuse, showing significant increases with certain contraceptive methods.

Specifically, the VTE rate ratios for combined pills, vaginal rings, patches, and progestin-only pills were 4.6, 4.5, 1.8, and 1.0, respectively. In contrast, IUDs, implants, and injections showed lower ratios of 2.4 and 5.7, respectively. When considering the excess VTE cases per 10,000 person-years, the combined pills were associated with an additional 8.0 cases compared to nonuse, with vaginal rings and patches contributing 6.0 and 6.1 cases, respectively.

Notably, the excess VTE risk varied among different formulations of combined oral contraceptives, with a range from 3.0 for those containing 20-µg estrogen with levonorgestrel to 14.2 for those containing third-generation progestins. These findings remained consistent even after adjusting for factors such as body mass index (BMI), smoking status, and family history of thrombosis.

The authors of the study emphasize that the variation in VTE risk across different hormonal contraceptive products highlights the necessity for personalized contraceptive counseling. This approach can help healthcare providers better inform their patients about the potential risks associated with various contraceptive methods, allowing for more tailored and safer choices.

It is also important to note that several authors of the study have disclosed relationships with the biopharmaceutical industry, which may warrant consideration when interpreting the findings.

This research serves as a critical reminder for women and healthcare professionals alike to stay informed about the risks associated with hormonal contraceptives, particularly regarding venous thromboembolism.