Researchers investigate the advantages and disadvantages of two types of contraceptive coils

In the "ThemenCheck Medizin" procedure offered by the German Institute for Quality and Efficiency in Health Care (IQWiG), interested members of the public can submit proposals for the assessment of medical procedures and technologies. On behalf of IQWiG, an interdisciplinary team of researchers led by Share to Care GmbH in Cologne investigated the advantages and disadvantages of two types of contraceptive coils (also known as intrauterine devices, IUDs) for preventing unwanted pregnancies, the copper IUD and the hormonal IUD.

Their conclusion: both types of IUDs are very safe and, compared to condoms or the pill, cost-effective contraceptive methods. They differ in their specific side effects: The hormonal IUD may cause more missed periods, while the copper IUD may cause heavier periods.

A question from a member of the public was the starting point for the ThemenCheck report

According to the results of a survey conducted by the German Federal Centre for Health Education in 2018, IUDs are the third most commonly used contraceptive method in Germany after oral contraceptives and condoms. They are used by around 10% of sexually active women. Two different types of IUDs are mainly used: the hormonal IUD and the copper IUD.

Both are inserted by a gynaecologist through the vagina into the uterus and removed at a later stage. The hormonal IUD releases a hormone that inhibits the build-up of the lining of the womb, preventing the fertilized egg from implanting. This means that menstrual bleeding may be shorter, weaker, and less painful. In contrast, the copper IUD prevents the egg from implanting by releasing small amounts of copper ions, which causes heavier menstrual bleeding in many women.

In the "ThemenCheck Medizin" procedure, a member of the public suggested comparing hormonal and copper IUDs under three aspects: How safe are these contraceptives? What are their side effects? And how are these side effects perceived by women who use them?

Advantages and disadvantages need to be weighed up individually

The team of researchers analysed eight studies that compared hormonal and copper IUDs. In addition to the results on safety, the studies also included many results on various side effects. However, no comparisons were found that included newer devices such as the copper chain or the copper ball.

Both IUD types are very effective, although the hormonal IUD is slightly better at preventing the fertilized egg from implanting. However, its hormonal effects may more commonly cause symptoms such as acne, nausea, depression or weight changes. There are no relevant differences between the two IUD types in terms of abdominal pain and health-related quality of life. Menstrual bleeding is more likely to be weaker or absent with the hormonal IUD and more likely to be heavier with the copper IUD.

Whether a woman chooses a hormonal or copper IUD depends mainly on her personal preferences. In particular, the effect of the IUD on menstruation is perceived very differently by women: Some find the reduction or absence of bleeding to be a positive effect, while others find it disturbing and unnatural. Comprehensive, balanced, and understandable information is therefore important so that a woman can choose the contraceptive method that is right for her.

The results of this health technology assessment (HTA) report can now be used to inform women who are interested in contraception with an IUD about its effectiveness and side effects. The HTA report can therefore inform the creation or further development of consumer information. This is supported by the easy-to-understand and shorter (German-language) presentation of the results of the HTA report – "ThemenCheck kompakt" – which was published on IQWiG's website at the same time as the full report

The "ThemenCheck Medizin" procedure

In a two-stage selection process, which also involves members of the public, up to five new topics are selected each year from all the proposals submitted. According to the legal mandate, these should be topics of particular importance for patient care.

The ThemenCheck reports are not written by IQWiG itself, but by external experts. Their assessment is published together with an easy-to-understand summary and a publisher's comment by IQWiG.

The Institute published the preliminary results of the (German-language) HTA report "Contraception: Comparison of hormonal IUD and copper IUD" in December 2022 as a preliminary ThemenCheck report and put it up for discussion. After the end of the commenting procedure, the report was revised and published in its final version in April 2023. The English translation of the report was published in November 2023.