Intrauterine contraceptives that do not fit well contribute to early discontinuation

To shed additional light on various aspects of intrauterine contraception discussed recently in a comprehensive review article and on the continued development of frameless copper intrauterine devices (IUDs).

An essential feature of intrauterine contraceptives is their long duration of action. However, this only applies in the absence of side effects. The importance of dimensional compatibility of the IUD or intrauterine system (IUS) with the uterine cavity should be stressed: IUD/IUS designs that fit will lead to high acceptability, a prerequisite with regard to continuation of use. Dimensional incompatibility, on the other hand, is a cause of cramping pain, erratic bleeding or menorrhagia, dislocation or expulsion and, as a result thereof, pregnancy. The size of the intrauterine foreign body, in relation to that of the uterine cavity, determines its acceptability and influences menstrual bleeding. Abnormal and heavy menstrual bleeding is an issue which has not been fully resolved. It is the most common cause of discontinuation of this contraceptive modality. The size of the IUD can be reduced without jeopardizing its effectiveness provided the effective copper surface is sufficiently large.

Properly designed and fitting IUDs and IUSs are associated with fewer side effects and greater user satisfaction. This, in turn, could increase usage of intrauterine contraception and thus reduce further the number of unintented pregnancies and induced abortions.