I would love for everyone to be able to choose non-hormonal birth control such as Fertility Awareness Method (FAM), but twenty years of clinical work has made me a realist. Some women like the simplicity of the copper IUD (see my last post). And some women like the flow-reducing effect of the hormonal IUD (Mirena or Skyla). I’ll go further and say that some women need that flow-reducing effect.
Unlike all other types of hormonal birth control, Mirena does not completely shut down ovulation and hormone production. Officially it doesn’t suppress ovulation at all, but one study found that it does suppress ovulation in 85 percent of cycles during the first year, and then in 15 percent of cycles after that. Remember, ovulation is beneficial because it’s the only way to make estradiol and progesterone.
Compared to Pills and implants, it delivers a lower dose of progestin. The blood level of levonorgestrel in Mirena users is about one-tenth that of Pill-users. But even that low dose can cause side effects. Please see the first Con point below.
It’s more effective than almost any other method, with a failure rate of just 0.7 percent.
After insertion, you don’t need to do anything or take anything, and it lasts 3 years (Skyla) or 5 years (Mirena).
Officially, fertility returns to normal almost as soon as you remove it.
It reduces menstrual flow by at least 90 percent, and that’s a huge Pro for very heavy periods. There are also natural treatments for heavy periods, which work well in younger women, but not so well for the flooding periods of perimenopause. If you’re 40-something and flooding, your only other options may be endometrial ablation or hysterectomy. Mirena is preferable to surgery.
It can also be helpful for endometriosis, and from an optimal health perspective, Mirena’s localised effect is vastly preferable to the systemic hormone-suppressing drugs typically used to treat endometriosis. (Fortunately, some women don’t require any hormonal treatment for endometriosis. For more information, please see Endometriosis: 5 Natural Treatments That Really Work.)
It releases the synthetic steroid levonorgestrel, which is the same progestin used in many Pills, and can cause acne, hair loss, hirsutism, depression, anxiety, headaches, breast pain, yeast infections, and weight gain. Obviously, this Con is a pretty big deal, and possibly a deal-breaker. But it’s still better than the full dose progestins found in all Pills, implants, injection, and Nuvaring.
It can cause ovarian cysts, which have been observed in 5 percent of Mirena users.
It suppresses ovulation some of the time (see first Pro point above).
It can cause irregular bleeding and spotting during first three to six months of use. After that, you may get no bleed (although you still cycle), or you may get a light period. (And in case you’re wondering—yes, that light period is a real period because it follows ovulation and the making of progesterone. To understand the difference between a real period and a Pill bleed, please see my new 3 minute animation.)
Your doctor has to insert it, and that will probably be somewhat painful. But just to clarify: It’s an in-office procedure that takes a few minutes—it’s not surgery. You’ll probably be instructed to take a painkiller like ibuprofen to ease the cramping, or your doctor may decide to use a local anesthetic (or more rarely, a general anesthetic ). One woman described IUD-insertion this way:
“It’s like a PAP smear test but a little weirder and more uncomfortable.”
It might come out. The chance of expulsion is about 5 percent, but it’s more common in younger women, breastfeeding women, and in women who had it inserted immediately following childbirth.
There’s a risk of pelvic inflammatory disease (PID) during the first three weeks after insertion, but only if you have a pre-existing infection with gonorrhea or chlamydia. That’s why your doctor should screen for those common conditions before inserting an IUD.
There’s a small risk of uterine perforation, which could lead to surgery. Perforation occurs in 0.1 percent of users (1/1000), but is more likely if you are breastfeeding.
If and when you want it out, you will need to see your doctor. In theory, you cannot remove it yourself, but actually many women do successfully manage self-removal, and one study found “little health risk from a woman removing her own intrauterine device”. The authors go on to say that IUDs would be more popular if women had the control to remove it themselves.
It doesn’t protect against STIs (sexually transmitted infections).
There are extra risks when breastfeeding. There’s a greater chance of expulsion and uterine perforation while breastfeeding. A small amount of levonorgestrel (about 0.1 percent of the maternal dose) enters the breast-milk, and there have been no long-term studies to assess its effect on infants.
Bottom line about the hormonal IUD (Mirena)
However, I also don’t like to see my patients suffer with flooding periods, adenomyosis, or debilitating endometriosis pain. So, as a realist, I will say there are times when Mirena is needed, and it is often a better choice than surgery or full-dose hormonal birth control.
Also, because Mirena permits some normal hormonal cycling, I view it as the least harmful of all the types of hormonal birth control.
Do women need periods?
There has been a bit of discussion lately about whether women even need periods anymore, and because Mirena suppresses bleeding, it has been part of the discussion.
First of all, do you need a period? Well, you don’t need a menstrual bleed per se, and you certainly don’t need a Pill bleed, which is not a period anyway. (Watch: There is medical reason to bleed monthly when on hormonal birth control.)
However, you do need the hormones estradiol and progesterone for their many health benefits, and you cannot make them without ovulating. And if you’re going to ovulate, then you will have a period two weeks later (either that, or be pregnant). Unless you take localised levonorgestrel (Mirena) which permits ovulation and hormones, but prevents a bleed by inhibiting the growth of the uterine lining.
“Do women need periods?” is the wrong question. The right question is: “Do women need to ovulate?”, and the answer is a resounding “Yes!”
If “menstrual suppression” is the goal, then Mirena is really the only reasonable option.
With most hormonal birth control, women bleed but don’t cycle. With a Mirena IUD, women cycle but don’t bleed.
Now, I’d love to hear your thoughts. Please comment.
Also please see previous post: The Pros and Cons of the Copper IUD.
Yours in health,