Mirena Coil – Preventing Pre or Post Conception?
Reach early forties these days and women are automatically fitted with a Mirena IUD, or so it seems. While it helps some to cope with heavy bleeding, there is an unspoken side which needs airing. Having asked a number of obstetricians if it prevents conception or prevents pregnancy (but not conception), all informed me the Mirena prevents implantation of the fertilized egg, which raises a number of issues. There are ethical issues such that some women may not be comfortable with this process for emotional, ethical or religious reasons and there is the issue as to why women are not being informed of the reality behind this doublespeak. Reading the manufacturer’s website does not make the ambiguity any clearer; it seems to be saying more by its silence!
Mirena IntraUterine System
I wonder if the manufacturer is trying to circumnavigate this problem by now saying fertilization is prevented because the hormone in this IUD thickens the mucous thereby damaging sperm motility and so preventing the sperm reaching the uterus. However, I don’t know if this saves the day; keep reading.
While women trust doctors, it’s incumbent firstly on doctors to be properly informed and secondly, the manufacturers to actively share reliable information because women do not need to be disempowered. Find below some information from various sites.
Definition of Pregnancy; The period from conception to birth. (Emphasis mine): click here
The US Mirena site talks about preventing pregnancy but not about preventing conception. Of course this is inaccurate as “pregnancy”, according to the medical dictionary (above), includes conception onwards. Click here
The global site says more by its silence than by what it actually does say. Click here
At http://www.lifeissues.org/abortifacients/ we are given an in-depth explanation, though not conclusive.
The IUD or intrauterine device is available in two different types in America. The hormonal IUD called Mirena, and the copper IUD called Paragard. Mirena releases levonorgestrel, which is a progestogen. Its primary function is to prevent implantation by the tiny developing human (embryo).
Preventing ovulation appears to function as a distant second. A study of women, one year after inserting the IUD, showed about one-half (45%) of women were still ovulating. After four years, 75% of women were ovulating. Obviously, the greater the number of women ovulating means the higher the chance for fertilization to occur. Other mechanisms of Mirena include thickening the mucus of the cervix, thus not allowing sperm to enter the uterus, or affecting the mobility or survival of sperm.
If fertilization occurs, most likely the tiny unborn child will be prevented from attaching to the lining of the womb and he or she will die. This is a very early abortion.
The copper IUD’s effectiveness comes from a continuous release of copper into the uterine cavity; however, they aren’t sure why this works. The general consensus is that this is accomplished by preventing implantation of the human embryo.
With both forms of IUD, if the woman becomes pregnant, she has a greater chance of having an ectopic or tubal pregnancy. This is when the tiny developing baby attaches to the lining of the fallopian tube and may threaten the woman’s life.
The IUD is not considered safe for women if they have not first given birth to at least one child, have a history of or had breast cancer, or have multiple sexual partners.
But the facts on Mirena seem to be misleading according to Physicians for Life in an article “Intra-Uterine Device (IUD)/Mirena by Bayer (updated 9/2011)” here:
…Since most of the progestin remains in the uterus, and very little of the progestin hormone is released into the blood, the ability to actually stop ovulation is questionable… Its presence in the uterus seems to indicate that there is primarily a ‘post-fertilization effect’ (adversely affects a new embryo as it enters the uterus, thus preventing it from implanting in the uterine lining — an early abortion).
The article continues:
According to the ambiguous “Mirena Prescribing Information” (link now moved), It is not known exactly how Mirena works. Mirena may work in several ways. It may thicken your cervical mucus, thin the lining of your uterus [negatively affects embryo implantation], inhibit sperm movement and reduce sperm survival. Mirena may stop release of your egg from your ovary, but this is not the way it works in most cases. Most likely, these actions work together to prevent pregnancy [ed. rather, ‘to prevent the establishment of the pregnancy in the uterus’]. Mirena can cause your menstrual bleeding to be less by thinning the lining of the uterus.
The IUD lost favor in the USA years ago because of several legal class-action suits charging serious damage/death to women from the effects of the IUD. According to these lawsuits and medical reports, many women suffered Toxic Shock Syndrome which can — or did — lead to death.
There are many shapes and components of IUDs. The action still appears to be a “post-fertilization effect” abortive, in that they prevent a developing human being, already fertilized in the fallopian tube, from attaching itself to the endometrium of the uterus.
“An intrauterine device (IUD) inserted into the uterus through the vagina and cervix usually interferes with implantation by causing a local inflammatory reaction. Some IUDs contain progesterone that is slowly released and interferes with the development of the endometrium so that implantation does not usually occur.” (Keith Moore and T.V.N. Persaud, The Developing Human: Clinically Oriented Embryology, 6th ed., Philadelphia: W.B. Saunders Comp. 1998, p. 58)
According to a study reported in the Dec 2002 American Journal of Obstetrics and Gynecology (“Mechanisms of action of intrauterine devices: Update and estimation of postfertilization effects”, by Stanford and Mikolaczyk, v 187, n6, 1699-1708):
“The possible mechanisms of action for the IUD in humans can each be classified as occurring before or after fertilization… Hormonal evidence indicates that the IUD does not generally inhibit ovulation in humans. The majority of women who are wearing hormonally active IUDs that reduce or eleminate (sic)menstruation still have ovulatory cycles as assessed by hormonal measurement and follicular ultrasonography.
“The possible postfertilization mechanisms of action of the IUD include the following: slowing or speeding the transport of the early embryo through the fallopian tube, damage to or destruction of the early embryo before it reaches the uterus, and prevention of implantation… It is well established that IUDs cause endometrial changes, with the type of changes present dependent on the type of IUD…
“The percentage of clinically recognized pregnancies that are ectopic [tubal] in users of inert and copper IUDs is about 3% to 4%, whereas for levonorgestrel and progesterone it is about 25%… These data support the existence of a post-fertilization effect for the IUD but cannot be used to estimate its magnitude…
“The Levonorgestrel-20 IUD (Mirena; Schering AG Pharmaceutical, Germany), developed in 1980…is highly effective to avoid clinical pregnancy, with a pregnancy rate around 0.1 per 100 woman-years. The levonorgestrel IUD has a minimal effect on the ovariam pituitary axis, and up to 85% of women are ovulatory during its use [i.e. these women still release an egg during each ovulation]. The rate of ovulation may increase with length of time that the device is worn.
“The strongest biologic effect of this IUD is local suppression of the endometrium… In addition, inflammation in the endometrium has bee demonstrated to be similar to that of inert IUDs. These endometrial effects result in decreased bleeding over time, and some women using the levonorgestrel IUD have amenorrhea [no bleeding]. However, amenorrhea does not necessarily imply that ovulation is not occurring but that it is primarily due to the endometrial effects…Cervical mucus favorable to the transport of sperm has been documented in the majority of ovulatory cycles during use of the levonorgestrel IUD.
“Overall, the consensus has been that levonorgestrel IUDs, like progesterone IUDs, act primarily by suppressing the endometrium, an effect that is likely to prevent implantation. However, endometrial effects may also result in the inhibition of sperm migration…
“With a clinical pregnancy rate of 0.1 per 100 women-years, the Levonorgestrel-20 IUD is thus estimated to be associated with the loss of 99.9% to 99.95% of all fertilized ova…
“In previous debates on the mechanism of action of the IUD, there was some discussion as to whether postfertilization effects were a “major” or “main” effect of the IUD. Our model illustrates clearly that, although the majority of pregnancy prevention occurs before fertilization, postfertilization effects make substantial and essential contributions to the effectiveness of all types of IUDs.
“With regard to the postfertilization effect of the IUD, it is likely that the majority of this effect occurs before the embryo enters the uterus.
“As discussed, the low recovery of ova from the uterus in IUD users, as well as the lack of hCG rise in more recent studies of IUD users, suggest that the major postfertilization effect is destruction of the early embryo in the Fallopian tube, in the same way that the major prefertilization effect is likely to be destruction of sperm and ova.
“For the copper IUD, this embryocidal effect may be more a result of inflammation and direct toxicity, whereas with the progestin IUDs it may result more from inhibition of transport through the Fallopian tube, along with prevention of implantation, preventing long-term viability of the embryo…
“We believe that these results have important implications for the counseling of women and couples who are considering the use of the IUD. Because our estimates are based on the best evidence currently available, we suggest that they could be used in clinical counseling for women who may object to postfertilization effects…”
Imager: Wiki Commons