An analysis of the corrosion process of the Nova-T IUD

Effective easing of the side effects of copper intrauterine devices using ultra-fine-grained Cu-0.4Mg alloy

Copper intrauterine device is one of the most adopted contraceptive methods with high effectiveness (over 99 %), low cost, spontaneous reversibility and long-lasting usage. However, the side effects induced from the initial burst release of copper ions (Cu²⁺) hinder the continuation of the Cu-IUD made of Coarse-Grained Copper (CG Cu). We proposed to tailor the bio-corrosion behaviors of better control of Cu²⁺ release via the addition of bioactive Mg into the Ultra-Fine Grained (UFG) Bulk Cu. Thus, UFG bulk Cu with 0.4 wt.% Mg was produced via equal-channel angular pressing. The microstructures of the UFG Cu-0.4Mg was observed using electron backscatter diffraction and transmission electron microscopy techniques. The in vitro long-term corrosion behaviors in simulated uterine fluid, cytotoxicity to four cell lines, in vivo biocompatibility and contraceptive efficacy were all studied on CG Cu, UFG Cu and UFG Cu-0.4Mg materials. The results demonstrate that both the ultrafine grains and the addition of bioactive Mg into Cu contribute to the suppression of the burst release of Cu²⁺ in the initial stage and the maintenance of high level Cu²⁺ in long-term release. Moreover, the UFG Cu-0.4Mg also exhibited much improved cell and tissue biocompatibility from both the in vitro and in vivo evaluations. Therefore, the contraceptive efficacy of UFG Cu-0.4Mg is still maintained as high as the CG Cu and UFG Cu while the side effects are significantly eased, suggesting the high potential of the UFG Cu-0.4Mg alloy as a new upgrading or alternative material for Cu-IUD. STATEMENT OF SIGNIFICANCE: The side effects from burst release of Cu²⁺ at the initial implantation stage of Cu-containing intrauterine devices (Cu-IUD) is one of the main drawbacks of these devices. In this work, an ultra-fine-grained Cu (UFG Cu) alloyed with a low amount of bioactive Mg was used for a Cu-IUD. The UFG Cu-0.4Mg alloy exhibited suppressed burst release of Cu²⁺ at initial implantation, while active Cu²⁺ release for long-term usage was maintained, comparable to coarse-grained pure Cu. Furthermore, the UFG Cu-0.4Mg alloy displayed significantly improved biocompatibility with human uterus cells and a much decreased inflammatory response within the uterus. Therefore, the side effects from Cu-IUD were eased, while high antifertility efficacy of the UFG Cu-0.4Mg alloy was maintained. The UFG Cu-0.4Mg alloy is promising for Cu-IUD.

Sexual function and metabolic/hormonal changes in women using long-term hormonal and non-hormonal contraceptives: a pilot study

Background

Female sexual dysfunction is a common condition that negatively impacts the emotional health and quality of life of the affected individuals. Long-acting reversible contraceptives (LARCs) are becoming increasingly popular due to their effectiveness and convenience. LARCs can be hormonal (etonogestrel releasing implant—ENG and Levonorgestrel intrauterine system—LNG) or non-hormonal (copper intrauterine device—CuIUD and copper-silver intrauterine device—SIUD). There are very few studies that assess the influence on LARCS on sexual function are lacking. This study aimed to assess changes in sexual function as well as metabolic and hormonal parameters in women after implantation with LARCs.

Methods

In this prospective cohort study, we assessed 80 women who visited the Military Police Hospital in Brazil for LARCs placement. The study participants were divided into 4 groups according to the type of LARC received: ENG n = 17; LNG n = 22, CuIUD n = 18 and SIUD n = 23. The four groups were evaluated twice (prior to LARC placement and approximately 3 months later) for sexual function, using the Female Sexual Function Index (FSFI) and Female Sexual Quotient (QS-F) questionnaires. Metabolic and hormonal parameters were also assessed using blood tests.

Results

ENG worsened sexual function according to FSFI and QS-F, across all domains. A decrease in sex hormone-binding globulin (SHBG) between stages was observed for all groups. We observed an improvement in sexual function for non-hormonal LARCs, specially SIUD. However this improvement was not statistically significant.

Conclusion

The use of non-hormonal LARCS improved sexual function. Etonogestrel implants, had a negative influence on sexual function, probably by blocking ovarian function, and thus reducing the production of androgens and estrogens.

A scanning electron microscopic study of the contraceptive vaginal ring

OBJECTIVE

To compare by electron microscopy the surface of vaginal contraceptive rings before and after use.

METHODS

A single ring was worn for 28 days by a volunteer with normal vaginal flora. This worn ring was then cut in half, with one half placed directly into fixative and the other half rinsed to remove visible mucus prior to being placed into the fixative. Another ring was taken directly from the package and placed in fixative. The surfaces of the three ring samples were studied by scanning electron microscopy at varying magnifications to ascertain if there was penetration of bacteria into the vinyl polymer or if the ring surface was altered with 1 month of use.

RESULTS

The ring half placed directly into fixative with visible mucus had cellular debris on its surface but no evidence of material penetration. The other half of the ring worn for 28 days and rinsed before fixation had a similar surface appearance to the unused ring.

CONCLUSIONS

The surface of the ethylene vinyl acetate contraceptive vaginal ring is remarkably uniform and after 1 month of use was without visible evidence of erosion, embedded bacteria or structural changes compared to an unused ring.

[Degradation of copper IUDs in utero. The process of metallic corrosion. A scanning electron microscope study]

OBJECTIVE

The present investigation was carried out in order to study the process of metallic corrosion of copper IUD's in utero, to precise its dynamics and location along the IUD and to appraise the influence of eventual calcareous deposition.

MATERIAL AND METHODS

A total of 461 copper IUDs representing four standard models were screened by means of optical microscopy. Especially typical samples were studied at higher magnifications under the scanning electron microscope. The obtained data were considered in terms of statistics.

RESULTS

It was possible to demonstrate a preferential corrosive activity in the lower part of the IUD without significant variations between the models. It was also possible to precise the steps of the process, to describe its most characteristic aspects and to study the eventual effect of severe calcareous deposition on corroded copper.

DISCUSSION AND CONCLUSIONS

Intrauterine copper corrosion is a normal process which occurs preferentially in the cervical portion of an IUD and can lead to the total metal loss. Both its initiation and evolution are submitted to strong individual variations. Thick and compact vaterite deposits may thwart copper erosion in case of drastic and rapid deposition.

[I.U.D. degradation in utero as a function of time: the phenomena of calcification. Radiocrystallographic and scanning electron microscopy study]

OBJECTIVE

A study was undertaken in order to determine the frequency of the process of calcareous deposition, to clarify the nature of the deposits, their arrangement along the IUD and their possible influence on the appearance of metrorrhagias.

MATERIAL AND METHODS

A total of 408 coopper IUD's belonging to four standard models were observed by means of optical microscopy at low magnifications. The most typical samples were studied under the scanning electron microscope and deposits analyzed by crystallography. The data were analysed statistically.

RESULTS

It was possible to determine both the frequency and the importance of the process of calcification according to the model of IUD and to the bearing time, to demonstrate a preferential location of concretions and to suspect a sensibility to the phenomenon variable according to the model. It was also possible to clarify the stages of the process of calcification, to describe its most characteristic aspects and to identify the essential component of calcareous deposits.

CONCLUSIONS

Calcification concerns roughly over 50% of IUD's in utero. It occurs preferentially on the fundic portion of an IUD. Obviously, the minimal time required for the phenomenon to start as well as to increase its intensity are submitted to strong individual variations. Concretions are composed of vaterite, a distinct variety of carbonate of calcium. They do not seem to be the primary cause of possible metrorrhagias.