Cells adherent to copper-bearing intrauterine contraceptive devices determined by monoclonal antibodies

Copper-T intrauterine device and levonorgestrel intrauterine system: biological bases of their mechanism of action

All intrauterine devices (IUDs) that have been tested experimentally or clinically induce a local inflammatory reaction of the endometrium whose cellular and humoral components are expressed in the tissue and the fluid filling the uterine cavity. Depending on the reproductive strategy of the species considered and the anatomical features and physiologic mechanisms that characterize their reproductive system, the secondary consequences of this foreign body reaction can be very localized within the uterus, as in the rabbit, or widespread throughout the entire genital tract as in women or even systemic as in some farm animals. Levonorgestrel released from an IUD causes some systemic effects, but local effects such as glandular atrophy and stromal decidualization, in addition to the foreign body reaction, are dominant. Copper ions released from an IUD enhance the inflammatory response and reach concentrations in the luminal fluids of the genital tract that are toxic for spermatozoa. In the human, the entire genital tract appears affected due to luminal transmission of the noxa that accumulates in the uterine lumen. This affects the function and viability of gametes, decreasing the rate of fertilization and lowering the chances of survival of any embryo that may be formed, before it reaches the uterus. The bulk of the data indicate that if any embryos are formed in the chronic presence of an IUD, it happens at a much lower rate than in non-IUD users. The common belief that the usual mechanism of action of IUDs in women is destruction of embryos in the uterus is not supported by empirical evidence.

Sympathetic and T helper (Th)2 bias may ameliorate uterine fibroids, independent of sex steroids

We propose that inadequate sympathetic bias and Th2 bias in the uterine environment contributes to the formation of fibroids, independent of the sex steroid status. We also propose that fibroids represent a modern maladaptation that partly results from decreasing exposure to seminal fluid, which contains catecholalmines, transforming growth factor beta1 (TGFbeta1), aldosterone, prostaglandins, and other factors that shift the uterine environment to sympathetic and T helper (Th)2 bias. Lower risk of fibroids is associated with pre-menarche, post-menopause, pregnancy, exposure to contraceptives, smoking, earlier age of first pregnancy, shorter interval since last pregnancy, higher parity, and non-obesity. These associations are currently attributed to alterations of sex steroids. However, the association may also be explained by the observation that pre-menarche, post-menopause, pregnancy, and smoking represent periods of sympathetic and Th2 bias. Furthermore, use of contraceptives, early age of first pregnancy, short interval since last pregnancy, high parity, abnormal pap smear, and non-obesity may represent surrogates for increased sexual activity and increased exposure to seminal fluid. Catecholalmines, aldosterone, TGF, and prostaglandins are among the seminal fluid components that promote sympathetic and Th2 bias. Vasectomized copulations protect against fibroids, an observation that undermines the steroid hypothesis and supports our hypothesis. The putative mechanism of action of uterine artery embolization (UAE) for fibroid treatment is starvation of blood supply, but the extensive collaterals that protect uterine perfusion would presumably also buffer against fibroid hypoperfusion. Instead, the sympathetic and Th2 responses to UAE-related ischemia may contribute to fibroid regression. A potential explanation for the association of fibroids with intrauterine devices may be a Th1 cell-mediated immune response to the foreign body, which may also enhance the contraceptive effect. Novel methods of preventing and treating fibroids by promoting sympathetic and Th2 shift through natural, pharmacologic, and neuromodulatory means are envisioned. Fibroids are likely a modern dysfunction given the high Darwinian fitness cost of fibroid-related infertility, and may be attributable to reduced intercourse frequency. Fibroids have been observed among animals in captivity that are presumably reproductively isolated.

The pathology of intra-uterine contraceptive devices

The IUCD is a simple and effective way of producing contraception without the need for patient compliance. It is not rendered ineffective by other drugs, as may be steroid contraceptives, and its side-effects, for carefully selected patients, are considered by most practitioners to be acceptably low (Van Kets et al. 1989).