The primary objective of the study is to assess the risks of intrauterine device (IUD) use in a study population that is representative for the actual users of the individual IUDs. The primary clinical outcome of interest is the uterine perforation rate.

This is a large, multinational, prospective, controlled, long-term cohort study that follows a series of cohorts. The cohorts consist of new users of different groups of intrauterine devices (IUDs). Primarily, a non-interference approach - with exception of the standardized diagnostic workup to identify uterine perforations - will be used to provide standardized, comprehensive and reliable information on these IUDs under routine medical conditions.

The primary objective of the study is to assess the risks of intrauterine device (IUD) use in a study population that is representative for the actual users of the individual IUDs. The primary clinical outcome of interest is the uterine perforation rate. Secondary objectives are among others:

• the time intervals between IUD insertion and uterine perforation
• impact of post-partal IUD insertion on the uterine perforation rate
• proportion of uterine perforations associated with IUD insertion with serious clinical complications
• the incidences of medically relevant adverse events associated with IUP use

The combined cohort will include 60000 women recruited in six European countries. Enrollment should begin in November 2006 and end in 2012. Patients should undergo follow-up for at least 1 year.

Recruitment of the cohort members will be conducted via a network of approximately 2000 gynecologists.

Enrollment procedures should not interfere with the prescribing behavior of physicians or with the individual needs of the participating women. Influence on the preference for specific oral contraceptives is to be avoided but significant efforts are to be undertaken to ensure standardized, comprehensive and reliable documentation of all baseline characteristics and adverse events during the follow-up period.

The study participants are women aged 18 or older who have a new insertion of an IUD and who are willing to participate in this cohort study. There are no specific medical inclusion or exclusion criteria. However, women who are not cooperative may be excluded from study participation. Also women with a language barrier will not be eligible for study inclusion.

This study will maintain scientific independence and will be governed by an independent Advisory Council. The Center for Epidemiology and Health Research in Berlin, Germany and its research team will be accountable for the Advisory Council (AC) in all scientific matters. The members of the AC wil be international experts in relevant scientific fields (e. g. epidemiology, gynecology and cardiology).

The study started after all relevant legal and ethical requirements had been fulfilled. Information on the identity of the patients and treating physicians will be kept separated from the clinical information throughout the study. All relevant national data protection laws will be followed.

Inclusion Criteria:

• women who have a new insertion of an IUD
• women who are willing to participate in this cohort study

Exclusion Criteria:

• women who are not cooperative
• women with a language barrier

Recruitment of cohort members will be conducted via a network of approximately 2000 gynecologists.

Information on adverse events was collected over a time period of 12 months.

All participants and health care providers were asked for adverse events at the follow-up 12 months after baseline.

In observational studies like EURAS-IUD, the possibility of bias and residual confounding can never be entirely eliminated. Thus, for risk estimates smaller than 2-fold, causality cannot be inferred confidently in view of alternative explanations.