Contraceptive implant link to blood clot risk

Friday May 11th, 2012

Switching from contraceptive implants to the Pill could help to reduce some women’s risk of developing serious blood clots, researchers say today.

The warning comes after a Danish study, published on the British Medical Journal today added to the weight of evidence that some contraceptives have a strong link to venous thromboembolism.

Professor Øjvind Lidegaard, of the University of Copenhagen, led the review of data on non-oral hormonal contraceptive use and first ever venous thrombosis in all Danish non-pregnant women aged between 15 and 49 years from 2001 to 2010.

All the women had no record of either blood clots or cancer before the study began and other factors, including age and education level, were taken into account.

The results are based on 9,429,128 observation years during which 3,434 confirmed diagnoses of first ever venous thrombosis were recorded.

The risk of venous thrombosis among women aged 15-49 years who did not use any type of hormonal contraception was on average two events per 10,000 exposure years. Women taking a combined oral contraceptive pill containing the hormone levonorgestrel saw their risk levels increase to 6.2 events per 10,000 exposure years.

Compared with non-users of the same age, women who used a skin patch had an eight times increased risk - 9.7 events per 10,000 exposure years – while women who used a vaginal ring had a 6.5 times increased risk - 7.8 events per 10,000 exposure years.

Use of a progestogen-only subcutaneous implant carried a slightly increased risk, while using a progestogen-only IUD was shown to have a possible protective effect. No reduction in risk was seen with long-term use of a patch or a vaginal ring, say the authors.

Based on the findings, the authors calculated that 2,000 women using a vaginal ring and 1,250 women using a skin patch should shift to a combined pill containing levonorgestrel to prevent one event of venous thrombosis in one year.

Outcomes of elective induction of labour compared with expectant management: population based study. Stock S et al. BMJ 2012;344:e2838 doi: 10.1136/bmj.e2838

Tags: Europe | Heart Health | Women’s Health & Gynaecology

Printer friendly page

Comments

1At 11/05/2012 10:42am Anonymous wrote

In fact the biggest risk is the patch and the ring, according to the article

Comment on this article: