Pregnancy is eight times commoner among women using copper intrauterine devices (IUDs) compared to levonorgestrel-releasing IUDs (LR-IUD), according the European Active Surveillance Study for Intrauterine Devices (EURAS IUD).

The study also shows that IUDs perforate the uterus about once in every 1,000 insertions. Seventy per cent of the 61,448 women enrolled in EURAS IUD were new users of LR-IUDs; the remainder were new users of one of around 30 types of copper IUD.

During the one-year follow- up, 26 women using LR-IUDs and 92 using copper IUDs became pregnant. The Pearl indices (the number of pregnancies per 100 woman years) were 0.06 with LR-IUDs and 0.52 with copper IUDs – an 84 per cent reduction after adjusting for confounders.

Seven pregnancies among women using LR-IUDs and 14 in those using copper IUDs were ectopic, a 74 per cent reduction.

Uterine perforations were uncommon: 1.4 per 1,000 LR-IUD insertions and 1.1 per 1,000 insertions of copper IUDs – a 60 per cent difference after adjusting for age, body mass index, breastfeeding when the IUD was inserted and parity. Thirty-five of the 81 perforations occurred while breastfeeding.

Perforations during breastfeeding were 6.3 times commoner with LR-IUDs and 7.8 times commoner with copper IUDs than among women who were not breastfeeding. No perforations caused serious illness or intra-abdominal or pelvic injuries.

“These data are important as they reinforce the safety and efficacy of intrauterine contraception, which is an important long-term, reversible option available to women,” Diana Mansour, consultant in community gynaecology and reproductive healthcare, Newcastle upon Tyne, told Pharmacy Magazine.

“Like many areas of healthcare, contraception is a topic on which pharmacists are trusted to offer counsel and guidance. It is, therefore, important that the pharmacy community is provided with relevant, up-to-date and accurate information about all the options available, to ensure that any misperceptions that exist around certain methods are dispelled and women are able to choose a method that suits their needs.”

_{(Contraception doi:10.1016/j.contraception.2015.01.011 and doi:10.1016/j.contraception.2015.01.007)}