Expulsion and continuation rates after postabortion insertion of framed IUDs versus frameless IUDs - review of the literature.

Background: Early intrauterine device (IUD) discontinuation after insertion immediately following aspiration abortion or after early medical abortion occurs as a consequence of expulsion of the IUD or removal due to side effects. These are often the consequence of the uterine forces impacting on the IUD due to spatial discrepancy with the uterine cavity causing pain, abnormal bleeding, and eventually, removal of the IUD. These women are candidates for repeat pregnancy as they often select less-effective methods or no contraception at all. Repeat abortion could be reduced by giving attention to these factors.

Study Design: In order to have an indication on the magnitude of the problem of IUD expulsion or discontinuation, we searched the MEDLINE database for clinical trials, randomized controlled trials, and prospective observational studies related to immediate postaspiration termination of pregnancy (TOP) and early medical abortion IUD insertion studies that reported IUD expulsion and IUD continuation rates.

Results: The search identified 17 clinical trials that were suitable based on the data they presented. The majority concerned T-shape IUDs, inserted immediately following surgical (aspiration) pregnancy termination. Two studies were conducted after medical TOP, and four studies were conducted with the frameless IUD inserted after surgical (vacuum aspiration) TOP. The results showed expulsion rates between 0.8% and 17.3% at 8 weeks, up to 5 years after insertion, respectively. In four studies with the frameless IUD, totaling 553 insertions, the expulsion rate was 0.0% in three of them. Follow-up in the latter studies varied between 5 weeks and 54 months. Reported continuation rates with conventional (framed) IUDs were between 33.8% and 80% at 1 year for studies providing 1 year rates and between 68% and 94.1% for studies reporting continuation rates at 6 months. Studies utilizing frameless IUDs reported 1 year continuation rate over 95%.

Conclusion: Frameless IUDs, due to their attachment to the uterine fundus, appear to be better retained by the postabortal uterus when compared with conventional framed IUDs. The absence of a frame ensures compatibility with uterine cavity anatomical dimensions, and may therefore result in improved acceptability and continuation rates in comparison with framed IUDs. Both these characteristics of the frameless IUD could help reduce the number of repeat unwanted pregnancies and subsequent abortions in some cases.