Women on birth control pills who take painkillers risk developing fatal blood clots

COPENHAGEN, Denmark — New research warns that women who are on birth control pills and also take common painkillers may have an increased risk of developing potentially fatal blood clots. The study specifically notes that non-steroidal anti-inflammatory drugs (NSAIDs) such as Nurofen, when used alongside hormonal contraception, elevate the risk of blood clots, also known as venous thromboembolism.

The risk was found to be higher for women using combined oral contraceptives containing third or fourth-generation progestins, as compared to those using progestin-only pills, implants, or intrauterine devices (IUDs) alongside NSAIDs like ibuprofen, diclofenac, and naproxen.

The researchers emphasize that the overall risk of developing a severe blood clot remains low, even among women using high-risk hormonal contraception. However, given the widespread use of both hormonal contraception and NSAIDs, they suggest that women should be informed about the potential risks.

Although NSAIDs have been previously linked to blood clots, little is known about how their use affects the risk of blood clots in otherwise healthy women who are also using hormonal contraception. The Danish research team used national medical records to track first-time diagnoses of blood clots among two million women, between 15 and 49 years-old, living in Denmark between 1996 and 2017. These women had no history of blood clots, cancer, hysterectomy, or fertility treatment.

Different types of hormonal contraception were categorized as high, medium, or low-risk based on their association with venous thromboembolism in previous studies. The new study also accounted for a range of potentially influential factors such as age, education level, pregnancy history, prior surgeries, high blood pressure, and diabetes.

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NSAIDs were used by more than half a million women while they were on hormonal contraception. Ibuprofen was the most commonly used NSAID, constituting 60 percent of usage, followed by diclofenac at 20 percent and naproxen at six percent. Over an average 10-year monitoring period, 8,710 venous thromboembolic events occurred, and 228 women (2.6%) died within 30 days of their diagnosis.

“Using high quality, linkable, national registries, this nationwide study adds new knowledge on the risk of a potentially fatal event during concomitant use of two drug classes often prescribed to otherwise healthy women,” says study author Dr. Amani Meaidi from the University of Copenhagen, in a media release. “Women needing both hormonal contraception and regular use of NSAIDs should be advised accordingly.”

The researchers add that the findings raise “important concerns” about simultaneously using NSAIDs, particularly diclofenac, and high-risk hormonal contraception. The team suggests that health authorities should consider these findings when assessing the safety of over-the-counter diclofenac. Additionally, both women on the pill and their doctors should consider alternatives to NSAIDs for pain relief.

“If treatment with NSAIDs is needed, agents other than diclofenac seem preferable, along with lower risk hormonal contraceptives such as progestin only tablets, implants, or intrauterine devices,” says Professor Morten Schmidt from Aarhus University Hospital.

The research is published in The BMJ.

South West News Service writer Stephen Beech contributed to this report.

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