Birth Control

From a message posted on Facebook:

 Is the pill safe? The International Agency for Research on Cancer in a 2007 study made by 21 scientists reported that the pill causes cancer, giving it the highest level of carcinogenicity, the same as cigarettes and asbestos. It also causes stroke, and significantly increases the risk of heart attacks. Several scientific journals have stated that the natural way of regulating births through the Billings Ovulation Method has no side-effects, and is 99.5 % effective.

The Billings Ovulation Method (BOM) is a method of natural family planning where women are taught to recognize when they have ovulated by examining their cervical mucus, allowing them to avoid intercourse during fertile periods or conversely, to have intercourse during fertile periods when pregnancy is desired. We used to call people who used the rhythm method “parents,” but BOM is more reliable than older abstinence methods.

I’m a big fan of oral contraceptives. They contributed to women’s liberation by giving us a reliable method of planning, delaying, or avoiding pregnancy.  They also have medical uses that go beyond contraception. Birth control pills (BCPs) have had such an important impact that they are known as simply “The Pill.” We have always known they were not 100% risk free; but we also know they are less risky than pregnancy itself. There are other methods of birth control; but they are generally less effective and less convenient.  For those who want permanent solutions, tubal ligation and vasectomy are available; but even they have occasional failures. What does science tell us about the effectiveness and safety of BCPs as compared to other methods? 


According to the Wikipedia entry, the Billings Ovulation Method has a failure rate of 0-2.9% with perfect use and 1-5% with typical use.  (They cite the original references for these figures). The corresponding numbers Wikipedia gives for “the pill” are 0.3% and 8%. The American Congress of Obstetricians and Gynecologists’ numbers for the pill are a bit less optimistic: they say “With typical use, about 8 in 100 women (8%) will become pregnant during the first year of using this method. When used perfectly, 1 in 100 women will become pregnant during the first year.”

A handy table on the FamilyDoctor website compares the failure rates of various birth control methods. It lists periodic abstinence methods as having a 20% failure rate, but that includes the less effective rhythm methods as well as the methods based on mucus examination. 

Cancer? It Causes Some Cancers and Prevents Others 

Information on cancer and oral contraceptives can be found here.  There is an increased risk of cervical cancer, but most cases are related to HPV infection, so hopefully the new vaccines will eliminate much of that risk. There is an increased risk of liver cancer in low risk populations but not in high-risk populations. The risk of breast cancer may or may not be slightly increased: studies do not agree.

On the other hand, the pill clearly reduces the risk of uterine and ovarian cancers. And a meta-analysis found that the risk of colorectal cancer is also decreased.

The magnitude of these risks is small. I couldn’t find any information about overall cancer risk: whether the increase in some types of cancer outweighs the decrease in others.

What the IARC Really Said 

According to the Facebook poster, the International Agency for Research on Cancer (IARC) said oral contraceptives were as carcinogenic as cigarettes and asbestos.  That’s not what the IARC said at all. It does classify estrogen/progesterone in the same group 1 category as cigarettes and asbestos, but all that category means is that there is sufficient evidence to prove carcinogenicity in humans. It does not in any way imply that oral contraceptives are as carcinogenic as cigarettes and asbestos: they aren’t.  And the IARC entry clearly states

There is also convincing evidence in humans that these agents confer a protective effect against cancer in the endometrium and ovary.

Other Risks

BCPs increase the risk of deep venous thromboembolism and ischemic stroke. There is disagreement over whether they increase the risk of myocardial infarction. The absolute risk of all these conditions is low. It is greater in smokers and in those with other risk factors, and it is lower for the newer low dose BCPs.

The ACOG has prepared an excellent patient education pamphlet  listing all the risks, benefits, side effects, and contraindications.  It concludes:

 The pill is a good choice for women who may want to get pregnant later. It is a safe and effective way to prevent pregnancy. It is easy to use, convenient, and reversible. The pill may protect against some cancers. Some benefits of pill use last months or years after you stop taking it. For almost all women, the benefits of pill use outweigh the risks.


Critics of hormonal contraception fixate on the risks, but there are also a number of health benefits. The ACOG patient information pamphlet explains that BCPs reduce the risk of

  • Cancer of the uterus and ovary
  • Ovarian cysts
  • Pelvic infection
  • Bone loss
  • Benign breast disease
  • Symptoms of polycystic ovary syndrome
  • Anemia (iron poor blood)
  • Ectopic pregnancy
  • Acne

They also

  • Help to keep periods regular, lighter, and shorter and reduce menstrual cramps
  • Reduce symptoms of endometriosis and fibroids
  • May help with migraine headaches and depression.
  • Can be used to schedule periods to avoid an inconvenient time (i.e. a wedding).

Other Options

There are many other birth control options: condoms, diaphragms, other hormone delivery methods like cervical rings and injections, IUDs, spermicides, periodic abstinence methods, and therapeutic abortions. Some methods have the additional benefit of protection against sexually transmitted diseases. Some methods require specific actions at the time of intercourse, which some people object to as interfering with spontaneity. The periodic abstinence methods have the disadvantage of requiring periodic abstinence.

I remember reading years ago (the reference is long gone and I don’t know if the information is still valid) that when all factors were considered including the risks from pregnancy itself when contraception fails, the safest method of birth control was to use condoms and do therapeutic abortions when they failed. That resulted in statistically less morbidity and mortality overall than any other method. Of course there are other considerations that make this a less than ideal option. Emotions and religion create a lot of bias in the area of birth control. I suspect some people who reject oral contraceptives as “unsafe” might be quite willing to take other medications that have a similar safety profile but are not connected to ideological concerns. 


BCPs are not risk-free, but the Facebook poster was wrong: their risks can’t be compared to the risks from cigarettes and asbestos. There are other good alternatives that some individuals may prefer for various medical and non-medical reasons. For any method of birth control, the risks must be weighed against the benefits. Pregnancy itself is far riskier than any method of pregnancy prevention.

The safest, most effective method of birth control is orange juice. You may ask “Before or after?” The answer is “Instead of.” Most women and their partners would not consider that a satisfactory option.

Posted in: Obstetrics & gynecology, Pharmaceuticals

Leave a Comment (32) ↓

32 thoughts on “Birth Control

  1. BillyJoe says:

    “Birth control pills (BCPs) ”
    In Australia it’s called the Oral Contraceptive Pill (OCP)

    “There are many other birth control options: condoms…”
    And there is this saying: like having a shower with a raincoat on.

  2. cellculturequeen says:

    “Can be used to schedule periods to avoid an inconvenient time”

    That one never worked for me, though. Even when I took two packs of pills without the one-week break, I still got the “period” at the exact time it would have happened with a break, only a little lighter. Which is odd because the bleeding one gets with the Pill is not actual menstruation, but a withdrawal bleeding caused by the lack of hormone intake. So how can it happen if there’s no withdrawal? I’ve been wondering about that for ten years.

  3. colli037 says:

    Another statistic regarding oral contraceptives you may want to include is the risk of serious complications or death from a “routine” pregnancy. This is not trivial, as eclampsia is reported in almost 3% of “normal” pregnancies, gestational diabetes in about 1% ( ref: BMJ. 2011 Oct 13;343: Risk of adverse pregnancy outcomes in women with polycystic ovary syndrome: population based cohort study. Roos N, et al ) and is MUCH higher in women with polycystic ovary disease.

    Death rate from pregnancy is rising in the US: Currently 14 per 100,000 (from a reuters article, dec 2010 citing cdc data)


  4. AlexisT says:

    May help with migraine headaches and depression.

    And may worsen them. I had to try 4 formulations before I found one that didn’t. In fact, I was told that current advice is that patients with a history of migraine with aura should not take combined BCP; after my first pregnancy, my GP flatly refused to prescribe them to me on that basis. Then I went and developed high blood pressure on top, so no one will.

    I’m not anti-BCP, far from it–that list is just rather one sided.

  5. MissMarnie says:

    @ cellculturequeen

    I’m not, in any way shape or form, a doctor or expert but I’ve been on the pill for more than half my life and a couple years ago switched to the 4-periods-a-year version. It took about a year for my body to get to the point where I had no spotting during the 3 months. If I were even a couple hours late taking a pill, especially near the end of the third month, I’d have spotting. The only way taking two packs in a row for a “special event” would have worked for me would be if I had taken quite a while to adjust my body to that cycle first.

    I can’t tell you why, all I can tell you is that my body seems to be fairly stubborn about its schedule.

  6. rork says:

    Sexually transmitted diseases underplayed.
    Not even mentioned as a possible risk associated with oral contraceptive use, only as a benefit of some “other options” in the section with that heading I think. Jumping off of tall buildings doesn’t increase the risk of cancer, but by the way, taking the stairs has an additional benefit of softening the landing, if you didn’t happen to take other precautions before jumping.

    I’d have wished for some data and more words designed to keep the readers very paranoid.

  7. Scott says:

    The safest, most effective method of birth control is orange juice. You may ask “Before or after?” The answer is “Instead of.” Most women and their partners would not consider that a satisfactory option.

    My mom always said it was aspirin.

    More specifically, the woman holding an aspirin tablet between her knees.

  8. AlexisT says:

    Rork: How are sexually transmitted diseases underplayed? Unless you have evidence that BCPs actually increase transmission, this is simply a risk of any BC method other than abstinence or condoms. Women using diaphragms and IUDs are also presumably more likely to forgo condom use, which is one of the reasons OB/GYNs are reluctant to fit IUDs in women who are not in stable, monogamous relationships.

  9. kathy says:

    Thanks for that Dr Hall. I’ve been needing a good link to post on Facebook for a while as answer to some of the stranger assertions re birth control pills.

    Here’s one lulu that arose just recently: That they cause breast cancer if used before you’ve had a baby. Reason: because until you’ve nursed a child your breasts are “immature”. No mention of what happens if you can’t nurse for some reason, or just don’t want to … presumably you will remain forever immature and can never use the pill! Also this group advocates that NO woman use the pill, including those who’ve already had and nursed several (sometimes a large number) of children.

    But then they are talking to those who already believe and therefore are unlikely to stop and examine a pre-accepted doctrine for it’s inconsistencies. I’ll post the link and hope for the best!

  10. Amy (T) says:

    a slight tangent: any news on BC for men (such as an oral contraceptive)?

  11. S.C. former shruggie says:

    I’ve wondered about pill safety for years, having had a classmate who suffered a minor stroke in her mid 20’s while on the pill. This is a good summary. Thanks, Dr. Hall.

    Kathy, it seems you’ve discovered an anti-pill crowd who are “pro-safe pill,” except they aren’t. Good luck with that.

  12. Fredeliot2 says:

    There is the traditional birth control pill for men, you put one in their shoe and they go limp.

  13. LMAO says:

    Harriet, I saw no mention in your post of BCPs as HRT. Specifically, the use of low-dose oral contraceptives for symptom relief perimenopausal women, even amongst those who require no birth control, seems to be something that comes up lately. I’ve seen indications that BCPs are supposedly beneficial, and possibly(?) preferable to “traditional” HRT (depending who you read).

    I’m just curious, as I’m in the very earliest stages of this process, and have begun looking into options for symptom relief. The BCP angle is interesting, because it seems to be mentioned most frequently in reference to my two primary symptoms: an astonishing new ability to gain weight (apparently by simply walking past the fridge), and annoyingly irregular periods (ugh). The opportunity for fewer, predictable periods (or no periods at all?) is just very appealing for some strange reason… ;-) not to mention being able to eat more than 1,000 calories a day. Sigh.

    So, should HRT be on the list of benefits? Or do the risk factors, particularly the vascular ones, outweigh them in us older chicks? As a frequent long-haul flyer, this one worries me a bit.

    Of course, it’s somehow amusing to me that I’m thinking about going on the pill in my late 40s after being so determined to get off and stay off BCPs in my 20s and undergoing tubal ligation after the birth of my last child in my early 30s! Irony anyone?

  14. Harriet Hall says:


    From a review article in the American Family Physician:
    “An estrogen dosage equal to 0.625 mg of conjugated equine estrogens is effective in postmenopausal women. However, this dosage may not be an appropriate estrogen supplementation for perimenopausal women. Women who are perimenopausal occasionally ovulate, and the low dose of estrogen and progesterone commonly used postmenopausally does not reliably suppress ovulation and, thus, does not eliminate the potential of unplanned pregnancy. Secondly, oral contraceptives may contain four to 10 times the equipotent estrogen dose of commonly prescribed postmenopausal estrogen therapy regimens. Therefore, for women in the perimenopausal years who are receiving oral contraceptives, it is important to identify when menopause occurs, so that the amount of estrogens prescribed can be reduced to safer levels.”

    HRT is indicated for relief of hot flashes and associated menopausal symptoms. If you do decide to take HRT, conventional advice is to take the lowest dose that helps and for the shortest time needed, and to re-evaluate every six months. Avoiding weight gain and regularizing periods are not generally accepted indications. And if you have no risk of pregnancy there would be increased risk and no benefit from choosing BCPs over the usual HRT regimens.

  15. Roadstergal says:

    We have always known they were not 100% risk free; but we also know they are less risky than pregnancy itself.

    Thank you for this post, and particularly for bringing this point up (and colli037 as well); I think a lot of folk, men particularly, don’t even consider that pregnancy itself can be a pretty dangerous condition, and causes long-term changes to a woman’s physiology even if it goes ‘well.’

    I was on The Pill (7/7/7) for most of my adult life, but have recently switched to Implanon. I’ve been on that for a year and change, and it’s just been magnificent; not having to think about birth control and carry pills with me wherever I go (or alter my sex life if I, say, forget them on a trip) has been, dare I say, liberating. I’m glad work continues to bring us birth control that is more convenient as well as safer and more effective (although I suppose two of those go hand-in-hand, if convenience increases compliance).

  16. Chris says:

    I was unhappy with birth control pills and the diaphragm, so after the birth of child #3 seventeen years ago I gave my husband two options: vasectomy or abstinence.

  17. nybgrus says:

    @ cellculturequeen:

    Having just finished up the repro module in medical school, I think I can shed a little light on your question.

    In brief, estrogen is used to build up the layer of cells (called the endometrium) that eventually becomes sloughed off during menses. After ovulation, estrogen levels drop and progesterone kicks in to maintain the endometrium. As the levels of progesterone drop you eventually get menses and the whole thing starts over again.

    If you are taking the pill and have had a regular 28ish day cycle and then try and extend that out to an extra month, what you are doing is attempting to maintain that endometrial layer longer. So partly because your natural hormonal rhythms are still in play (granted a small influence in this scenario), but mostly because the endometrium is simply not very stable past the 28th day, you will get some light bleeding. After getting your body used to the new “cycle” and the endometrium becomes more stable, then you can avoid said bleeding. For some women this happens very rapidly – for some, it takes longer (as MissMarnie pointed out). But for those that don’t adapt rapidly, switching back and forth (i.e. just skipping on period occasionally) will certainly lead to greater difficulty actually skipping the period.

    Hope that helps!

  18. BillyJoe says:

    “hot flashes”
    In Australia it’s hot flushes.

    “the woman holding an aspirin tablet between her knees”
    There’s a way around that.

    “I gave my husband two options: vasectomy or abstinence”
    There’s a third option which I bet he never told you about.

  19. Chris says:

    BilllyJoe, we are still married. I also am the only one who knows the passwords to the financial accounts.

  20. rork says:

    AlexisT: Sorry if it wasn’t obvious I was thinking mostly about condom use. I actually found it hard to find studies comparing STD transmission rates between condom and pill.

  21. DugganSC says:

    The other side effect I’d heard of was premature aging of the cervix although I don’t have the literature on hand to find the citation (I believe it came in the packet of materials I got from my church when registering for marriage classes). Personally, I’m not a big fan of chemical contraceptives simply because medicine is, and has always been, a method of controlled poisoning used to control diseases. Taking medicine when healthy seems somewhat counterintuitive, especially when, as you noted above, the non-chemical ways can be just as effective. My beliefs are pretty firmly based on ideological grounds, admittedly. I’m firmly against abortion and I think that most contraceptive methods, particularly the ones where you don’t have to put any conscious thought into them, fosters a mindset that if you do get pregnant, it’s not your fault because you took precautions, increasing the chance of someone snuffing an innocent life that might be inconvenient. I’d like to think people would be more rational, but every year, you get lawsuits being filed over people suing equipment manufacturers for safety equipment which failed by chance or misuse rather than by any fault in design.

    {shakes head} Anyhow, if I’m not careful, I’ll pull out my soapbox. I figured I would direct the assertion about the cervical aging to you and see if it has any basis.

  22. Solandra says:

    “I gave my husband two options: vasectomy or abstinence” The pull out method, when used correctly, has about the same rate of effectiveness as condoms. Been using that for 5 years with no mishaps. I think more people should know about it. And pre-ejaculate doesn’t contain sperm unless it was hanging out in the urethra, but washing and urinating before sex gets rid of that. Do not confuse this with the religious “family planning” crap, either. Totally different.

  23. annappaa says:

    @Amy (T) — I wrote an article about male birth-control options here a couple of months ago. RISUG sounds really cool and promising, and will hopefully be available in the United States within a few years.

  24. Chris says:

    The pull out method, when used correctly,

    Too much work. And why bother when a couple already have enough children?

  25. lilady says:

    @ Chris:

    “BilllyJoe, we are still married. I also am the only one who knows the passwords to the financial accounts.”

    Might I add to your clever comment:

    My husband also knows the passwords to our financial accounts…but is somewhat clueless about the investment choices I have made to provide for our retirements.

    We also had “enough” children after the two we had and found that condoms (when actually used) were very effective to avoid unwanted pregnancies.

    Dr. Hall, I often wondered just how high the doses of hormones were, when I took the pills for four year, starting 45 years ago. I suspect that I had more than a lifetime dose of these hormones.

  26. CMCo says:

    “Can be used to schedule periods to avoid an inconvenient time”

    I always took this to mean stopping the yellow [blue, white, pink, whichever your 7/7/7 is] one week early, not one week late. (In my experience, it’s worked pretty well; i.e., the cycle comes one week earlier than usual, and is completed in time for whatever event.)

    Great article, btw – as I’m approaching my late 40’s and wondering if it’s safe to still be taking the pill, it’s good to know that there are at least as many benefits as risks.

  27. CMCo says:

    “Can be used to schedule periods to avoid an inconvenient time”

    I always took this to mean stopping the yellow [blue, white, pink, whichever your 7/7/7 is] one week early, not one week late. (In my experience, it’s worked pretty well; i.e., the cycle comes one week earlier than usual, and is completed in time for whatever event.)

  28. kortikosteroid says:

    wouldn’t it be easier if all men had a sufficient amount of sperm stored away in some freezer, enough to father a reasonable amount of children in the future, and then just underwent a vasectomy?

    that way, we would get rid of all unwanted or unplanned pregnancies, women wouldn’t have to worry about the risks of birth control pills, couples wouldn’t have to use unsafe methods, and well… things would just become so much easier for everyone. am i missing something here?

  29. DugganSC says:

    That would make for an interesting individual solution, but, much like any situation with vasectomies, it would either require a great deal of oversight (making sure everyone gets snipped) or a great deal of trust (no really, honeybunch, you don’t need to use anything. I got the operation). The first isn’t going to fly anymore than government control of reproduction generally does (even in China, the only country I know of that mandated birth control, multiple children were common enough that there was a set of standard fines). The second… well, does it leave us in any better of a position than today?

    Also, on a visceral level, I feel uncomfortable with the idea of metaphorically hiding my heart in a locked box. It seems like someone always finds the box and puts a stake in it in the stories. Similarly, what am I supposed to do when the sperm bank’s refrigerator fails, or there’s issues in the impregnation and I’m starting to run low on samples?

    Lastly, you’ll get the same religious resistance to it as with other forms of birth control. Whether you want to argue it’s about personal responsibility or about control, surgical impotency isn’t likely to go over any better than chemical impotency. And therein, you’re going to get a lot of friction with the above point about how for it to properly work would need a very strict government structure.

    Ultimately, it’s an interesting idea, but the type of thing that shows up in a sci-fi book where they’ve conveniently waved away how they got there.

  30. Scott says:

    That idea also doesn’t take into account STDs. When it comes right down to it, any form of birth control other than condoms is either a backup, or suitable for those in a long-term monogamous relationship. Accordingly, any attempt at universalizing birth control just doesn’t make sense – condom use would still be very widely required.

  31. KS”t it be easier if all men had a sufficient amount of sperm stored away in some freezer, enough to father a reasonable amount of children in the future, and then just underwent a vasectomy”

    Hmm, unless you store a whole lot of sperm away, you are may have one of two problems. If you are doing some sort of at home insemination you will have to account for error. Many couple don’t get pregnant the first, second, third try…it can while. If you are instead thinking of using reproductive endocrinology methods such as IUI or IVF to increase reliability, then you are talking about much bigger expense, more risks and negative side effects to mother and the possibly fetus(es).

    Having been through fertility treatment, which did not suit me, My opinion is I’d much rather use birth control or a condom with spermicide for birth control than rely on technology for reproduction.

  32. kortikosteroid says:

    for safety reasons, every man should of course have his samples stored in two different freezers. i don’t know about the amounts needed- would they really be that big? as far as i know, when breeding animals, one single ejaculate is usually enough to inseminate multiple animals, as it is diluted.

    of course, my idea is sci-fi rather than reality at this point. and even if it was possible, most men wouldn’t feel comfortable with undergoing a vasectomy and relying completely on a freezer for replication. but from a mere rationalistic point of view, i still think my idea is great! ; )

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