Birth Control Side Effects You Should be Aware of (Cancer, Weight Gain & More)

Birth control pills are widely recommended for a variety of conditions beyond their use as a contraceptive. 

Many women take birth control to help 'balance' their hormones, stop acne, or treat menstrual irregularities. 

And while the pill may help with some of these conditions you always have to be aware of HOW they are working and what trade-off you are making. 

Understanding how birth control pills work to suppress your normal hormone production can help you understand how they work and why they may cause some serious problems. 

Among these side effects include serious conditions such as weight gain, autoimmune disease, and cancer. 

Before you use birth control, of any type, you should be aware of all of these potential side effects. 

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The Big Problem(s) With Birth Control Pills

If you know anything about me you probably know that I am not a huge fan of birth control pills. 

My dislike of them has nothing to do with their impact reproductive function but instead because of how they work and what they to do the body!

It drives me crazy that doctors are so willing to prescribe birth control pills at the drop of the hat but balk at prescribing other hormones such as thyroid hormone, testosterone, progesterone, and so on. 

There is obviously a bias that exists against what are known as bio-identical hormones and not against the man-made synthetic alternatives. 

What you may or may not be aware of as a patient is that all of the birth control pills that we have available are synthetic and man-made. 

What does that mean?

It means that they do NOT contain an exact replica of the hormones (estrogens and progesterone) that your body produces naturally. 

This may not sound concerning at first glance because aren't pharmaceutical medications based on plant compounds but made more effective through man-made intervention?

While that may be true, it doesn't mean that birth control pills are necessarily safe or effective because of that. 

You should NOT consider your hormones in the same category as say something like aspirin or ibuprofen. 

Your body has spent decades (depending on how old you are when you read this) utilizing the hormones that you were MEANT to produce. 

When you start taking birth control pills you are effectively shutting down the natural production of estrogen and progesterone (1) from your body and letting the birth control pills take over. 

Again, it may sound benign but you have to realize that when you do this you are letting a man-made synthetic hormone take over the function of the hormones 

Yeah, but my hormones are already out of balance so won't this bring balance to my hormones?

This is how birth control pills are "sold" to patients but it isn't true at all. 

Birth control pills don't bring balance to your hormones any more than ibuprofen solves your headache when you take it. 

Birth control pills completely shut down your hormones and mask whatever issues were causing your problem just like ibuprofen masks the pain of your headache without solving the cause of it (which could be something like muscle tension). 

And the fact that birth control pills are synthetic and man-made is precisely why so many women struggle with symptoms when using them. 

Do I think that OCP have value? Yes, but I am not a fan of how often they are prescribed and how little information is provided to patients before they start taking them. 

So, with that in mind, let's talk about some of the side effects that you MAY experience when using these medications. 

Let's Examine the Side Effects of Birth Control Pills

When I talk about the side effects of birth control I am mostly talking about the side effects that I find most concerning. 

There will always be some minor symptoms associated with birth control which are not too bad. These would be the everyday common symptoms that can occur with pretty much any medication. 

Common symptoms (2) that you may experience include:

  • Bloating
  • Breast tenderness
  • Spotting
  • Headaches (migraines are more concerning)
  • Mood changes
  • Irritability
  • Missed cycles
  • Nausea
side effects of birth control pills

This obviously doesn't represent the full list of side effects but you should be aware that they exist. 

I don't really consider these symptoms to be all that bad. 

The side effects that I am more worried about are listed below. 

These are the side effects that you as a patient may or may not be aware of and side effects that your doctor may not even tell you about. 

Let's talk about these: 

#1. Breast Cancer

Perhaps the most alarming side effect, and probably the least talked about, is that of breast cancer. 

We have known that there is an association between breast cancer (which is an estrogen-sensitive tissue) and the use of estrogens for decades (3). 

To be fair, this risk even exists if you use bio-identical hormones such as estradiol.

But this risk is dose-dependent and really only occurs if you use unopposed estradiol (without progesterone). 

The key difference is that the risk of breast cancer with the use of oral contraceptives and synthetic hormones (4) is higher and, at least to our current knowledge, cannot be mitigated with the use of progesterone. 

So comparing these two things is not fair (bio-identical hormones and synthetic hormones), even though it is a strategy employed by pharmaceutical companies. 

They would rather you get confused when you look at the various hormones available and the risk associated with breast cancer. 

If you believe that all forms of hormones (synthetic and bio-identical) result in an increased risk of breast cancer then you may be more likely to not care which one you use. 

But that would be a mistake. 

Newer studies show that the use of bio-identical estradiol AND progesterone confer a BENEFIT against breast cancer. 

While the risk of breast cancer with synthetic OCP is right around 20% or so. 

That means that you have about a 20% increased risk of breast cancer when using oral birth control pills (5). 

This is a serious risk and something that should be considered by every woman BEFORE using OCP. 

I'm not 100% convinced that the risk of breast cancer associated with the use of birth control pills is related to the synthetic hormones, however. 

I feel that there are probably other factors at play such as the conditions which caused you to be placed on the pills, to begin with. 

Let's say you were started on them because of irregular periods, heavy bleeding, acne, or menstrual cramps. 

All of these symptoms point to an imbalance of estrogen and progesterone in your body which will exist whether you are placed on birth control pills or not. 

And if they sit there smoldering for decades it's possible that those factors may increase your risk of breast cancer independent of the pills. 

A lot of information needs to be parsed out and we are probably a long way from figuring it all out. 

As you might imagine, pharmaceuticals are not chomping at the bit to undergo studies on their own medications which may prove them risky to the public. 

You might believe that they would do this but they have a track record of keeping side effects to themselves (unfortunately). 

As recent as 2011, GlaxoSmithKline paid out 3.5 billion to settle lawsuits because they did not disclose that their medication caused an increased risk of heart attack. 

#2. Weight Gain 

If the breast cancer risk didn't concern you then maybe the chance that you will gain weight might. 

This is also another somewhat confusing and controversial topic among people.

On one side of the argument, you have patients who adamantly believe that birth control causes weight gain and on the other side you have doctors which say that isn't true (6) because there aren't enough studies to prove it. 

weight gain on birth control

I'm not really sure why both things cant be true and, indeed, that's what I see happen. 

It's possible for some women to experience weight gain while taking birth control pills just like it's also possible for some women to lose weight or stay weight neutral. 

And these counteracting effects can simultaneously wipe out statistical significance in studies by doctors. 

But this does not mean that birth control pills don't cause weight gain, far from it. 

Indeed, I've seen a great many patients who immediately gain 15-20 pounds right after taking birth control pills (of any type). 

weight gain in OCP use

Doctors will point to studies which suggest that birth control pills increase water weight, increase breast tissue density, and may increase muscle mass (7) as the cause of weight gain. 

While these may be true (although not necessarily desirable), they still leave out the fact that estrogen has a direct impact on your adipose tissue (8) (fat cells). 

It's well known that high levels of estrogen stimulate weight gain. 

Even if studies don't prove it, I can tell you from personal experience that estrogen can cause weight gain. 

When I was starting out and learning about hormone replacement therapy I put my own wife on a relatively moderate dose of estrogen (which included both the active estrogen and protective estrogen). 

She gained 13 pounds in around a month or so (without any other changes) and wasn't happy at all. 

Don't worry, we fixed the issue, but I learned very quickly not to use estrogen in pre-menopausal women unless absolutely necessary. 

So to suggest that birth control pills can never result in weight gain is disingenuous. 

But to say that they always cause weight gain is probably equally as disingenuous.  

So, what should you do as a patient considering OCP? 

If you are overweight and considering the pill then try to lose weight FIRST before you go on it. 

Not only will this prevent excess weight gain when you use it but you may find that losing weight will probably result in balance to your hormones. 

If you have to go on the pill then try to get your weight under control before you do. 

We know from conditions such as menopause that overweight women tend to gain even more weight during the transition

It's not fair, but this is how it works out. 

#3. Menstrual Irregularities

I know birth control pills are often used to fight menstrual irregularities but they can definitely result in even more irregular periods. 

This tends to be more common for women who use birth control as a contraceptive but it can occur in pretty much any woman. 

Remember:

Birth control pills contain synthetic hormones. 

These synthetic hormones still activate estrogen receptors on the tissues in your body. 

If you put too much activation on cells in your uterus (the cells that produce and grow the uterine lining) then you may end up with irregular periods or changes to your cycle. 

Most of the time, however, the doses found in birth control are basically high enough to pretty much shut down the normal production of FSH, LH, estradiol, and progesterone in your body. 

Many birth control pills contain a placebo which acts like a "cycle" but really it's just a withdrawal bleed (9) as you take a break from the synthetic hormones found in the pills. 

The fact that your hypothalamic-pituitary-ovarian axis (10) is shut down by the synthetic hormones is part of the reason that some women have a hard time with conception after they stop taking the pill. 

We were taught in my medical school that it can take up to 12 months for some women to regain their fertility as this system tries to kick back into gear. 

Infertility is a symptom associated with a condition known as post birth control syndrome which can be caused by this issue. 

This is why some women will continue to have menstrual irregularities for many months (11) even after stopping the pill. 

#4. Melasma

I've treated many women with melasma (including my wife). 

Melasma, also referred to as the mask of pregnancy, is a condition which is thought to be caused by excess estrogen which can stimulate your melanocytes (12). 

melasma is a potential side effect of birth control pills

Melanocytes produce melanin which causes pigmentation in your skin. 

This condition tends to cause discoloration and hyperpigmentation of the skin on the face in certain patterns. 

How do birth control pills contribute to melasma?

From the synthetic hormones found inside. 

Some studies show that as high as 24% of patients on birth control (13) may experience some degree of melasma. 

Remember:

Your body has a hard time differentiating between synthetic estrogen and bio-identical estrogen. 

Even synthetic hormones can trigger and activate estrogen receptors on melanocytes much like your own native estrogen can. 

The most difficult component of this condition is that it can be so hard to treat once you have it. 

You might think that it will be as easy as just stopping the offending cause but it's rarely ever that easy. 

Even women who obtain melasma from pregnancy still maintain it after birth, even when estrogen/progesterone levels normalize. 

The same is true for women who get melasma from birth control. 

This is not a very common side effect to experience when taking birth control and it appears to have a fairly large genetic component to it as well. 

So not all women who take birth control will experience it but certain women with the genetic predisposition to should beware. 

#5. Yeast Infections

Yeast infections of all types are found more frequently in women who use birth control pills (14) compared to those who don't. 

You're probably familiar with yeast because it causes several different conditions including yeast overgrowth (candida) in the gut, oral thrush, and vaginal yeast infections. 

Candida can also cause life-threatening conditions but these are very rare and really only occur in people who have severely compromised immune systems. 

More important to our discussion is the fact that yeast (candida) overgrowth syndromes tend to be more common in women who use birth control. 

This is an issue because yeast overgrowth, especially in the gut, can cause serious symptoms. 

You're probably aware of all of the cleanses, diets, and supplements that target yeast overgrowth and candida. 

Some of these symptoms include acne, depression, food cravings, weight gain, abdominal pain, and so on. 

And these conditions are notoriously difficult to treat.

If you're put on birth control pills then this may be something that you need to pay attention to. 

Why does it occur?

It seems to be related to the impact that estrogens have on certain cells in your body which allows yeast to grow and thrive. 

Taking estrogen may set the stage to allow for colonization and growth which can then spread to other tissues. 

For instance, if you have yeast in your intestinal tract then you are much more likely to suffer from vaginal yeast infections. 

#6. Increase in Autoimmune Diseases

This one may be surprising but several studies have shown a link between the use of hormonal contraceptives and the development of autoimmune diseases (15). 

Autoimmune diseases occur when your own body attacks itself. Depending on how and where this attack occurs helps to define the autoimmune disease. 

In the case of birth control pills, taking them may increase your risk of developing multiple sclerosis (MS), ulcerative colitis (a type of IBD), Crohn's disease, lupus, and interstitial cystitis. 

Interestingly, oral contraceptives seem to decrease the risk of developing hyperthyroidism such as Graves' disease

Even the use of progesterone-only oral contraceptives has been associated with conditions such as eczema, contact dermatitis, alopecia (hair loss), acne, and hives. 

Not all of these conditions are considered autoimmune disease but it is widely recognized that they all come from disordered immune function. 

It's pretty clear based on the studies and the evidence that birth control pills are doing something to the immune system, in certain individuals, which predisposes them to develop these conditions. 

how birth control pills increase your risk of autoimmune disease

To be fair, it's certainly possible to develop these conditions even without taking birth control. 

And, it's probably also possible that many women who develop these conditions might have done so whether they used birth control or not. 

But, even if that is true, it seems that birth control may be accelerating the event or acting as an inciting event which triggers them. 

If you are considering taking birth control pills and you already have a history of autoimmune like conditions then it may be wise to think twice. 

#7. Blood clots

Blood clots are obviously a serious potential consequence of using birth control pills and one that many doctors are aware of. 

In fact, most doctors should at least mention this as a potential issue before you start taking the pill. 

The rate of developing a blood clot for most women is incredibly low but taking birth control pills can increase that risk by up to 3.5x (16). 

This is not a huge risk but it is definitely something you should be aware of. 

Blood clots tend to form in the veins on your legs and may travel to your lungs. 

Blood clots in your veins are known as deep vein thrombi and when/if they travel to your lungs it is known as a pulmonary embolism. 

Estrogen tends to have a pro-coagulant effect on the blood (17). 

For practical purposes, you can think of this as making your blood more sticky and more likely to form a clot. 

Most clots form the in the 'deep veins' of your legs because the blood flow there can be relatively still or quiet compared to other parts of your body. 

These types of clots are more likely to form when you are sitting still like when you are traveling long distances or taking long airplane rides.

Nowadays, the risk can be diminished by taking low dose birth control pills. 

Most of the women at risk for developing blood clots are those over the age of 35 and those who also smoke. 

While the risk isn't huge and may not necessarily compare to the other side effects listed here, you should definitely still be aware that it could potentially happen. 

What to do Instead

I'm not 100% against birth control pills despite all of the side effects listed above. 

But I do think that you, as the patient, should exhaust every other alternative and therapy available to you BEFORE you go on these pills. 

This may include the use of dietary changes, the use of medications to help insulin resistance, the use of targeted supplements, stress management, and so on. 

All of these therapies can potentially help truly reverse or bring balance to whatever issues that you are dealing with. 

My experience suggests that between these natural therapies and the intelligent use of progesterone (a bio-identical hormone) you can solve most of the issues which are causing you problems. 

Even if you can't 100% solve them there is still a good chance that you can dramatically reduce your symptoms. 

I have more in-depth articles on these topics but I wanted to include a couple of therapies below as well:

  • Change up your diet - If you aren't already eating clean then now is the time. Sugar and processed and refined carbohydrates are especially bad for women's hormones as they lead to menstrual problems and insulin resistance. Cut out the sugars, bread, pasta, etc. and you should notice an improvement. Make sure to also simultaneously increase the number of greens that you consume (I mean seriously increase them). Cut back the sugar and put organic greens into your mouth on a daily basis. 
  • Take over the counter supplements - There are a plethora of supplements that have been clinically shown and proven to help balance female hormones. I've written about these hormones extensively in other guides so I would encourage you to check them out here. Some of these include supplements which help your body eliminate estrogens, help reduce inflammation, help curb appetite cravings and so on. My two favorite for women are probably indole-3-carbinol and DIM
  • Exercise (the right way) - Exercise (but not too much) can help balance testosterone (18) levels and regulate your cycle. It can also help manage stress which can impact your sex hormones. 
  • Consider using progesterone cream or pills - Bio-identical progesterone can help balance naturally high levels of estrogen and many women with high estrogen (known as estrogen dominance) tend to have low progesterone levels. It may be possible to take some progesterone and bring balance back to your hormones without using the pill. 
  • Treat your gut - Your gut helps to control your appetite and even helps regulate your hormones. Eating low-quality foods which are high in sugar can cause gut dysfunction which may trigger further food cravings and more hormone issues. Treat your gut by putting GOOD food into it and by using supplements such as probiotics
  • Take a multivitamin - Taking a multivitamin is a great way to provide your body with a supply of essential vitamins and nutrients. This is a great place to start if you aren't sure what you should be doing. You should, of course, do other things as well, but don't neglect this step. 

I understand there may be situations where you need to be placed on birth control pills for various reasons. 

If that is the case you should still seek to try and reverse whatever issues were causing your imbalance, to begin with, and realize that the longer you stay on birth control pills the more likely you are to experience some of the negative side effects listed above.

Using Non-Hormonal Alternative Contraception

If you are using birth control pills for contraception (to avoid getting pregnant) then you may be happy to know that there are long-term non-hormonal alternatives available. 

The method that I most frequently recommend for my patients is the copper IUD. 

The copper IUD should be differentiated from the hormonal IUD known as Mirena

Mirena is an IUD but it also provides your body with a steady low dose of hormone while it is implanted. 

Like we've been discussing, these hormones are not bio-identical and may, therefore, cause issues and side effects. 

You can opt for the copper IUD which does NOT secrete any hormones into your uterus. 

The copper IUD is still very effective at preventing unwanted pregnancy and doesn't come with all of the side effects associated with synthetic hormones (19). 

For whatever reason, Doctors tend to always push the Mirena over the copper IUD so you will probably have to ask for it by name. 

If you just say you want an "IUD" your doctor will probably default to the Mirena. 

Do not let this happen!

Studies have shown that both Mirena and the copper IUD are equally effective (20) in preventing pregnancy so the preference should be on the NON HORMONE SECRETING alternative (the copper IUD in this case). 

The copper IUD isn't perfect though as there is a theoretical risk that it may secrete low levels of copper into your body. 

This would be unwise to use in situations where you suspect you have copper overload. 

If you elect to take to use the copper IUD it's probably a good idea to also take Zinc every single day. 

Zinc helps bring balance to copper so it's worth using in this setting (plus Zinc also helps balance other hormones such as insulin!). 

Conclusion

I don't think you should be afraid of birth control pills but you should absolutely be aware of all potential side effects BEFORE you start them. 

Educate yourself, learn as much as you can, and try to take control of your body. 

If there's one thing that I want you to take from this article it's that it is possible to naturally manage your hormone levels without suppressing estrogen and progesterone with the pill. 

Yes, it may be hard, but taking this approach will result in more stability for your health long-term. 

Now I want to hear from you:  

Are you currently taking birth control pills?

If so, are you experiencing any of the symptoms listed here?

Have you gone off of the pill? If so, did you experience any of the issues we discussed?

Are you considering using the pill? If so, for what condition?

Leave your comments or questions below! 

References (Click to Expand)

birth control side effects
Dr. Westin Childs

Dr. Westin Childs is a Doctor of Osteopathic Medicine. He provides well-researched actionable information about hormone-related disorders and formulates supplements to treat these disorders.He is trained in Internal Medicine, Functional Medicine, and Integrative Medicine. His focus is on managing thyroid disorders, weight loss resistance, and other sex hormone imbalances.You can read more about his own personal journey here.

7 thoughts on “Birth Control Side Effects You Should be Aware of (Cancer, Weight Gain & More)”

  1. I started having severe muscle pain and swelling in feet/ankles while taking Levothyroxine (50mcg) so I stopped taking it and I need a cane to walk! Is this a side effect of stopping the medication?

    Reply
  2. I actually feel worse off of birth control. I went off of it for over a year at 34 and had weight gain, hypothyroid and no period. Tests reflected LOW levels of estrogen and progesterone. Is that why I feel better ON it? Is the weight gain off of it low estrogen? Thoughts on this? I tried bio hormones but didn’t feel much better.

    Reply
    • Hi Kat,

      Birth control suppresses your body’s ability to produce hormones and it can take your body many months (sometimes years) to recover and to start producing hormones on its own. You could be dealing with this right now which could easily explain why you feel worse off of it. But going back on it would not necessarily be the best solution.

      Reply
  3. I am 48 years old and have had premenopausal symptoms for about 4 years (ex-smoker). My periods just became so painful and extra long (10 days or more) that after a couple of ultrasounds revealed that nothing was amiss my PCP put me on a combination pill called Femynor. Now I’ve been recently diagnosed with hypothyroidism and started on 25 mcg of levothyroxine about a week ago. I feel less depressed and have a better mental attitude about my usual severe chronic pain (spinal OA, scoliosis, and DDD) but just don’t feel as good as I would like. I’ve been suffering for a while and was wondering if the thyroid issue could be related to another sex hormone imbalance that I should treat differently. I also get the aimoviq shot for chronic migraine.

    Reply
  4. I’ve looked for 22 years for this information! I knew my weight gain had to do with the birth control pills but had no support in that conclusion. I also had rounds of yeast infections/antibiotics/candida that was unexplained until now. My sudden weight gain came on after having to use zyrtec for the also unexplained violently itchy rashes that came on at that time. This information validates what I suspected: that they were all interconnected. These turned into “lipidema”, which I’m now seeing as a result of leptin resistance and hormone imbalances with zinc and selenium deficiencies.

    Reply

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