Silverlily and Goldlily IUDs: do alloys create a new generation of intrauterine contraceptive devices?

Silverlily and Goldlily IUDs: do alloys create a new

generation of intrauterine contraceptive devices?

I Batar

University of Debrecen, Department of Obstetrics and

Gynecology, Debrecen, Hungary

Introduction The surface of copper in copper-containing

devices oxidizes by time. Corrosion destroying the metal reduces the life span

of the IUD because the copper becomes fragmented, and disappears from the

plastic frame. The latest novelties, the alloy-containing devices try to solve

this problem, and at the same time enhance the contraceptive effect by

electrochemical mechanism.

Objective Two IUDs (Silverlily and Goldlily) having

different alloy metals (Cu/Ag and Cu/Au, respectively) have been studied for

effectiveness and safety in a prospective clinical trial.

Materials and methods The overall performance of 3,290

Silverlily and 4,055 Goldlily IUDs were analyzed in a human phase IV study. Life

table (LT) calculation was used for statistical evaluation.

Results At the end of the first year of follow-up 1,954

and 2,253 women were at risk in the Silverlily and the Goldlily group,

respectively. The cumulative woman-month of use was 27,762 in the Cu/Ag and

32,628 in the Cu/Au IUD user populations at 12 months. One-year relevant

device-related termination rates/100 users for Silverlily and Goldlily were as

follows: pregnancy 0.7 for both devices, expulsion 1.9 and 2.0, removal for

bleeding/pain 6.1 and 5.3, respectively, and removal for other medical reasons

2.2 for both devices. There were not statistically significant differences

between the groups in these relevant competing risks. However, terminations for

all competing risks (including removals for planned pregnancy and other personal

reasons as well) showed a significant difference (Chi-Square = 4.2673;

Probability < 0.05) with rates of 13.7 for the copper-silver device, and 11.8 for the copper-gold IUD. It is explained by the fact that significantly more Silverlily (2.4) than Goldlily (1.3) were removed for planned pregnancy (Chi-Square = 7.5674, Probability < 0.01).

Conclusion Both devices showed good protection against

unwanted pregnancy. Due to the low termination rates for other reasons, the

continuation was high at the end of the first year of use: 86.3% in the Cu/Ag

and 88.2% in the Cu/Au group. One may suggest that using different copper/noble

metal alloys in intrauterine contraception leads to a new generation of IUDs.

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