Of course, it also lowers sex drive[1], while causing weight gain, cancer[3], and heart problems[4].
For historical reasons IUDs are uncommon in the US. This is unfortunate. They aren't perfect, but they are relatively cheap, extremely reliable, and remarkably safe. Depending on the type, they also have few or no side effects. Worth considering...
[1]: This one arguably isn't a health benefit, but in many ways it's huge. With a few exceptions, humans are sexual beings, and frequency of sexual encounters correlates highly to a range of positive health outcomes, happiness, avoidance of depression, and strong long-lasting relationships.
[2]: This one confuses people, because it also prevents cancer. Best evidence is that it has a fairly strong protective effect on ovarian cancer, but causes breast and cervical cancer. The net effect on total cancer rates is still unknown; it's certainly not a clear cut benefit though, and it may be a clear net negative. (As always, these sort of epidemiology numbers are a real headache to parse. Comparing a big effect on a rare event to a small effect on a common event is very tricky. Still, anything that boosts breast cancer rates is kind of scary.)
[3]: This one is clearcut. Hormone based birth control causes a range of heart issues, from heart attacks via clots, to cardiovascular diease. We're still trying to figure out how big this factor is, but it's already clear that if you have any risk factors (ie, you're overweight, or have a family history of heart disease) you should NOT be on combined oral contraceptives, and any hormone based birth control is very iffy.
I have known several women with non-hormonal IUDs, and they all have reported the side-effect of mild-to-extreme aggravation of menstrual cramping. When the body is trying to clear out, it just doesn't like having a foreign agent that won't budge.
From personal experience with both hormonal and non-hormonal contraception (Pill vs. copper IUD), I suspect the reported aggravation is due to the fact that the Pill reduces said "aggravation", and once you are off the hormones, you feel like it's worse but it's really just back to normal.
In general, when the IUD is installed correctly, the body does not perceive it as a foreign object or try to reject it or move about and puncture holes or increase the levels of copper in the blood or [insert another myth that seems to make intuitive sense but has no scientific or observed basis].
(There is one myth that has near truth to it. The common misconception that you have to have been pregnant to get it. This is not true either - the uterus just has to be big enough to house the IUD comfortably and and it's virtually guaranteed that a post-pregnancy uterus is. However for most pre-pregnancy women this not a problem either, and a size check is the first step during the installation process).
The benefits on the other hand are real, and huge. Reduced risk of hormone-associated cancers, noticeably increased sex-drive, better hair, nails, and skin, not having to take a pill every day, less money, statistically better protection from pregnancy, the list goes on.
It's not perfect, but the side-effects are small and it's the most effective form of birth control besides true abstinence (as opposed to "virginity pledges," et al). Works for three years, nothing to remember, no risk of uterine perforation like IUDs, and none of the nasty estrogen side-effects.
I also mentioned heart problems, but I limited my response to only those side-effects Lazare mentioned in order to stay on-topic.
Side effects of Oestrogen-containing contraceptives that don't seem to be caused by Progestin-only contraceptives include:
Increased risk of cancer
Increased risk of heart disease
Bone density reduction
Blood clots / Stroke
Increased sensitivity to UV (and associated skin cancers)
Reduced breast-milk production. This isn't very detrimental to one's own health, but does effect the health of the child.
The only down-side of Progestin-only pills versus Oestrogen-containing pills is that it is extra important that it be taken at the same time every day for full efficacy. Obviously the implant doesn't suffer from this drawback.
I know every geek here research the hell out of everything... and so i don't trust even my doctor when he/she can't show (or i can't find later) pertinent and well controlled studies before messing something in my body. i'm pretty sure you did your research, but those articles and discussion here shouldn't be taken as 'proof' of anything as the comment i replied to sounded to imply.
also, i have a paranoia that no hormone/protein/enzyme does less then a few things in your body. if they list only one or two effects, it's because they have no clue what else they do.
prolactin was believed to only affect the milk production in mamals for a long time (and water-salt control in fishes). now there's some other dozen effects on the body including neuron fiber formation.
well, non-hormonal IUDs function by stimulating the uterus to produce hormones (prostaglandins) - So they can actually have more significant side-effects than hormonal IUDs.
All hormonal contraceptives are not created equal.
Cancer and heart problems are side-effects of estrogen or combination (estrogen + progestin) hormonal contraceptives. Progestin-only contraceptives (which include Implanon, Jadelle, and Mirena) have never been shown to cause cancer or heart problems.
As always, don't look for medical advice from HN.
(dfc was obviously referring to contraceptive treatments for debilitating menstrual pain and irregularity)
It should be noted that estrogen doesn't cause the cancer. The cancer exists and actually feeds on estrogen.
A woman's body is likely to find and destroy the defective cells before it's too late, but when you're taking hormones to overpower your body, you also have the risk of feeding the cancerous cells.
This is news to me. I have never heard/read anything that casts hormonal birth control in such a negative light. Do you have any pointers to more information? It has always been my understanding that hormone based birth control was a huge win for women's health...
The impact on sex drive is fairly well known, I think. Google turns up a bunch of references[1][2]. The impact on weight is apparently cloudy; birth control pills almost universally list that as a side effect on the packaging, but studies have failed to turn up a reliable link. (Silly me; never trust drug company materials, even if they seem to be casting the drug in a negative light.)
I understand there's some evidence that birth control may cause depression, but I don't know that there's a definitive answer. (Google mostly just turns up anecdotes from people convinced that their depression is caused by their birth control; not really helpful.)
The argument over which way the cancer risk goes on balance is all over the net; there's a decent roundup on Wikipedia[3]. If you dig into it a bit, it's still pretty unclear, mostly because there haven't been a lot of studies.
The heart stuff is, compared to cancer, much more solid. Again, the internet is full of stuff about this. I don't know of any comprehensive roundups, but google will turn up a TON of stuff.
Anecdotally the hormonal IUD's seem to have more of an effect on sex drive than the old fashioned pill. Me and the wife found that out after a clinic doctor gave her a prescription for it saying it reduces the risk of cancer (true, but unanimously agreed that it isn't worth it).
It must be noted that the anecdotal 'warnings' IE weight gain, depression, etc. may be a result of the well known drop in sex drive. Because, you know, sex has this mystical property that releases pleasure chemicals that reduce depression. Depression having the obvious side effect of weight gain. Also the impact on the hormone cycle anecdotally causes cravings.
The pill itself might not have side effects of weight gain, but I'd bet it's side effects do.
There are thousands of forums with women discussing all the negative side effects of birth control. Off the top of my head, you can visit http://iud-divas.livejournal.com/, which is women who are considering/have IUDs, and many of them report the negative (often severely so) effects of previous hormonal birth control usage. Otherwise you can visit bedsider.org, which talks about side effects for all birth control methods.
The pill is an incredible win for women's health. Unfortunately, not all women can use it effectively, safely, or comfortably.
For historical reasons IUDs are uncommon in the US. This is unfortunate. They aren't perfect, but they are relatively cheap, extremely reliable, and remarkably safe. Depending on the type, they also have few or no side effects. Worth considering...
[1]: This one arguably isn't a health benefit, but in many ways it's huge. With a few exceptions, humans are sexual beings, and frequency of sexual encounters correlates highly to a range of positive health outcomes, happiness, avoidance of depression, and strong long-lasting relationships.
[2]: This one confuses people, because it also prevents cancer. Best evidence is that it has a fairly strong protective effect on ovarian cancer, but causes breast and cervical cancer. The net effect on total cancer rates is still unknown; it's certainly not a clear cut benefit though, and it may be a clear net negative. (As always, these sort of epidemiology numbers are a real headache to parse. Comparing a big effect on a rare event to a small effect on a common event is very tricky. Still, anything that boosts breast cancer rates is kind of scary.)
[3]: This one is clearcut. Hormone based birth control causes a range of heart issues, from heart attacks via clots, to cardiovascular diease. We're still trying to figure out how big this factor is, but it's already clear that if you have any risk factors (ie, you're overweight, or have a family history of heart disease) you should NOT be on combined oral contraceptives, and any hormone based birth control is very iffy.