Mechanism of action of intrauterine devices
Last reviewed: 23.04.2024
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There are several theories explaining the mechanism of contraceptive action of intrauterine devices.
Theory of abortive action of intrauterine devices. Under the influence of intrauterine devices, endometrial trauma, release of prostaglandins, increased muscle tone of the uterus, leading to the expulsion of the embryo in the early stages of implantation.
Theory of accelerated peristalsis. The intrauterine device increases the contractions of the fallopian tubes and uterus, so a fertilized egg gets into the uterus prematurely. The trophoblast is still inferior, the endometrium is not prepared to receive a fertilized egg, as a result of which implantation is impossible.
The theory of aseptic inflammation. An intrauterine device, like a foreign body, causes leukocyte infiltration of the endometrium. The resulting inflammatory changes in the endometrium prevent implantation and further development of blastocysts.
The theory of spermatoxic action. Leukocyte infiltration is accompanied by an increase in the number of macrophages that carry out phagocytosis of spermatozoa. Addition of copper and silver to the intrauterine device enhances the spermatoxic effect.
Theory of enzyme disorders in the endometrium. This theory is based on the fact that intrauterine devices cause a change in the enzyme content in the endometrium, which has an adverse effect on implantation processes.
It is unlikely that the contraceptive effect of intrauterine devices is caused by any single mechanism.
Efficacy of intrauterine devices
The effectiveness of this type of contraception (Pearl index from 2 to 0.3) is virtually unrelated to the qualities and characteristics of the consumer. Since it requires only periodic monitoring of the presence of an intrauterine device after its administration.
Medical control of women using intrauterine devices
When using intrauterine devices, it is advisable to examine the woman 3-4 weeks after the introduction of the contraceptive, then preventive examinations, in the absence of complaints from the woman, can be conducted every 6 months.
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