I found this thread helpful as my wife and I were recently agonizing over whether she should use a Mirena IUD. I thought I would try and return the favor by describing the results of a great deal of research and discussion.
As background, my wife and I are both Catholic and are the parents of four children. After #3 was born, my wife had “idiopathic menorrhagia,” or heavy bleeding with no identifiable cause. In her case, it meant that she bled for close to half of her cycle and that on the heaviest days, she had to use double protection (tampon + heavy pad). She was reluctant to leave the house on those days. After #4, we began to explore treatment options. My research revealed, and the doctor confirmed, the following options:
- Take NSAIDs (e.g., ibuprofen) in heavy doses just before and during one’s period. My wife had been doing this without much relief.
- Take tranexamic acid (aka Lysteda), which has been shown to provide significant relief of heavy periods. Unfortunately, it has also been shown to cause stomach upset, and my wife has IBS.
- Take prometrium, a natural progesterone that is derived from yams. This is hormonal but does not normally prevent pregnancy. The most common side effect is extreme drowsiness, which causes some doctors to recommend taking it just before bed. This option had an appeal, but the drowsiness was a problem - my wife is still breastfeeding and needs to be able to get up in the night to attend to our infant.
- Take progesterin-only pills or “mini-pills.” This is hormonal and contraceptic. There is also research which suggests that it is not particularly effective.
- Insert the Mirena IUD. This is hormonal, but much less so than the prometrium or mini-pill - it releases about as much synthetic progesterone in a week as prometrium or the mini-pill would deliver in a day, and it delivers it to the uterus and not to the bloodstream, so side effects are typically either not present or only modestly present. The main problems with the Mirena are: a) it is contraceptive; and b) it is a foreign object that can very seldom cause severe problems (e.g., perforation of the uterus).
My wife’s doctor strongly recommended that she take one of these treatment options, and recommended that she take the Mirena given her circumstances. We were reluctant to do this. So I researched the issue and found out the following:
Use of Mirena can be permissible under the doctrine of double effect (i.e., if you take it to treat heavy menorrhagia, it is morally acceptable). There are articles to this effect on the internet by Mark Repenshek, Ph.D., a Catholic ethicist at the Columbia St. Mary’s health care system, and by Msgr. James Mulligan, a medical ethicist for the Diocese of Allentown, PA.
The biggest problem with Mirena from a Catholic perspective is the potential that it acts as an abortifacient. Mirena treats heavy periods by thinning the lining of the uterus. That prevents heavy periods, but it also makes it difficult for a fertilized egg to implant. The doctrine of double effect requires some proportion between the problem being treated and the problem that the treatment causes. If Mirena prevents fertilized eggs from implanting, then there is no proportion: the problems of heavy periods are not proportionate to the evil of causing a potential life to be aborted.
However, research indicates that the Mirena does not in fact have an abortifacient effect. This seems counter-intutive - if it thins the uterine lining, then it will create an abortifacient effect if the egg is fertilized. The Mirena materials say that the manufacturer isn’t sure how it works: it may work by preventing fertilization (which is not abortifacient) and may work by preventing implantation (which is abortifacient).
However, the uncertainty on this issue appears to be caused by the fact that research into how IUDs worked was limited when the Mirena was approved for use - the doctors back then knew that it worked but weren’t sure how. Research since then (consisting especially of a number of tubal flushing studies) indicates that in women with Mirena IUDs, eggs almost never get fertilized: the Mirena IUD primarily acts by preventing fertilization, so there is typically nothing that could implant and thus no actual abortifacient effect. Dr. Repenshek refers to some of this research in his 2006 article. Additional studies, done after 2006, confirm this. As a result, the Mirena is eligible for double effect treatment because there is some proportion between what it does (prevent fertilization) and what it treats (heavy periods).
- There appears to be some confusion about whether a woman who is using a medical treatment which has a contraceptic effect MUST refrain from sex entirely. I’ve seen things all over the place on this issue on the internet and no clear answer. It is clear that a woman who is not having sex can use a contraceptic medical treatment with no ethical problem - a nun could use Mirena without issue. The question is whether and to what extent a married couple must abstain from sex if the wife has Mirena.
My impression is that a married couple must abstain as needed to prevent the possibility of abortifacia: i.e., the couple should use NFP and abstain during what would otherwise be a fertile time, but they may have sex during what would be non-fertile times. Mirena tends to eliminate periods in some women, making NFP difficult to use, but couples should make some effort to abstain so as to further preclude the possibility (even though the research indicates that it is slim to none) of abortifacia.
I did a great deal of research about Mirena. I discussed it with a deacon and a priest and sought spiritual direction from them. Both indicated that given our circumstances (extremely heavy periods, but openness to life as exhibited by four kids to date), we could use the Mirena in good conscience.