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The Effects of Birth Control: an Interview with Professor Johannes Bitzer, Part 1

Want to find out more about the effects of birth control on female body? Read the first part of our exclusive interview with prof. Johannes Bitzer, an Ex-president of the European Society of Contraception and one of the leading experts in the field of birth control.

It is the first part of our two-part interview with professor Johannes Bitzer. The second part of the interview is here.


If you look at just possible health risks and side effects, we could say that one of the least “risky” methods is probably the copper IUD. 

It doesn’t have a negative impact on metabolism or the cardiovascular system. If you place it properly, there are no major gynecological complications. Taking the very broad view, we can say the copper IUD has a very good risk-to-benefit profile.

The most complicated issue is actually with hormonal contraception. There are two basic types of hormonal birth control pills. One is the so-called combined hormonal contraceptives containing progestogen and estrogen. The other group contains just progestogen. 

All the COCs have low but important cardiovascular risk, especially of venous thrombosis. It can be a dangerous complication. Fortunately, it's very rare, but the risk is there, and it increases when you take COCs.

If you take hormonal contraceptives without estrogen, you don’t have this thromboembolic risk. So progestogen-only contraception has also a favorable benefit/risk profile. Moreover, progestogens can be taken as pills, as implants, as intrauterine systems.

Here it is more of a tolerability issue. The side effects you might have are not dangerous, but are rather uncomfortable, especially those regarding bleeding irregularities. And here the combined oral contraceptives have additional benefit issue: they regulate the cycle, they are good for your skin, they protect against certain health conditions.

All in all, the most complicated picture is with the COCs: there are very good aspects, but there are also risks. On the general level, copper IUDs are probably the ones that have the least risks followed by progestogen-only contraceptives in the second place.

Many studies have shown that the most effective are these long-acting methods we’ve been talking about, namely IUDs and hormonal implants. They are almost 100% effective. Nothing is exactly 100%, but they are close — around 99.5%. 

Other methods like the pill would also be similarly effective, but not in what we call a typical use. You need to take the pill every day, and people have difficulties sticking to the schedule.

So if you aim for maximum effectiveness of the birth control regardless of your own discipline, long-lasting birth control methods are the best.

There is a difference between the different times when you forget your pill. The most dangerous time is when the user restarts the pill after 7 days of break. Most women still have the «classic» pills where you have pills 21 days, and then start a 7-day break. Forgetting the pill within the first week after the break is quite dangerous because the follicles already grow. When they’re not suppressed by regular intake during the first week, a breakthrough ovulation occurs.

So when you forget one or even two pills during the first week, you should take emergency contraception, you’re not protected very well anymore. If you forget one or even two pills in the middle of your package, just take the pills you forgot later. This is not so dangerous, because you have seven days of regular intake which are good for the suppression of the ovaries. These are the general rules. When a woman is not secure, she should tend to emergency contraception in addition to her pill.

Regarding breasts getting bigger: what sometimes happens, especially in the beginning, is the estrogen component in the pill causing some water retention. This is not really growing of the breasts, it is more of water retention inside the glands, the tissue. Rashes are rare, I must say. They usually have nothing to do with the pill, actually. This may really be a coincidence. There are rare occasions when women’s bodies react to the progestogen in the pill, especially when they go into the sun. They might get skin coloration. It is rare, but that is a consequence of the pill.

Yes, they can help treat the symptoms of PCOS. They cannot heal PCOS, but we can quite effectively treat the symptoms.

The most important symptoms are cycle irregularity, stronger bleeding, and skin symptoms — acne and hirsutism. This can be very effectively treated by birth control pills, especially those that contain what we call antiandrogenic progestins. It counteracts the effect of testosterone, thus effectively treating the symptoms.

Read this next: a detailed interview about PCOS with Professor Tahir Mahmood

This has been studied very intensively because there was the fear for women who start the pill very early and stop 20 years later. Do they get problems with their cycle or fertility? Indeed, some women may not find their menstruation after stopping the birth control pill. This is called amenorrhea. The studies have shown that these women had this problem preexisting, but they didn't realize it because they took the pill, so they had regular bleeding. The pill itself doesn’t cause endocrine problems, but the endocrine problems may appear after stopping the pill. 

Classic endocrine problems are PCOS or other forms of so-called hypothalamic amenorrhea, which preexisted, but it didn’t show until women stopped the pill. Regarding fertility, it has become very clear that pill use even protects fertility. You get less infection, less ectopic pregnancies, of course. Regarding fertility, you’re better off using the pill than not.

We should be careful when talking about the cause of these serious conditions because these conditions are usually caused by a combination of factors coming together. The birth control pill is one of the risk factors.

There is some association between the pills and stroke, a very low risk, but there is some association. There is no association with aneurysm. An aneurysm is something inborn, it has nothing to do with the pill. So, the important issues are venous thrombosis and arterial complications like myocardial infarction or stroke. They are very, very rare, but if you take a sample size of hundreds and thousands of women, there is some association.

In general, we can say there is no clear scientific evidence of weight gain.

There have been a lot of studies comparing birth control users with non-users or IUD users for six months or even a year. Unfortunately, in all the groups women gain weight. We don’t know why, but the studies didn’t find a difference. In clinical practice, I think there are some women who really experience the anabolic effect of the progestogen. And I have to believe them — and I believe them — that they feel they gained weight. But probably they are very few cases where it is really the pill that makes them gain weight.

Spotting is normal during the first three months and even later in the sense that it’s not a sign of a disease. But what happens is that you give these hormones externally and the mucosa in the uterus has to adapt to these hormones. You give both hormones every day, which is different from the natural cycle. This may lead to the fact that the endometrium has some little breakthrough bleeding, some spotting. 

It’s not a disease, it’s not dangerous. It usually disappears, but also may come back a little bit later. Again, it’s not something to be worried about.

There are contraindications for each method. If you consider combined hormonal methods ( the pill, patches, vaginal rings), the main contraindications are connected to the risk of thrombosis: family history or personal history of thrombosis and also specific genetic issues, like thrombophilia, for instance.

Then there are age-related issues — women after 40 should be very careful with combined oral contraceptives when they are overweight and smoke more than 15 cigarettes a day. 

But there are also some false beliefs about contraindications. Having breast cancer in the family, for instance, is not a contraindication. Although having breast cancer already is a contraindication. 

For progestogen-only contraceptives, there are almost no contraindications (specific rare diseases and some cancers) 

For the copper and the hormonal IUDs, the only contraindication is bleeding when you don’t know where it comes from, or an acute infection of the uterus. 

For men, there is nothing known really. Men are less in danger with their birth control options.

She doesn’t need to wait, there is no negative long-term effect. You just get off the contraceptives and can get pregnant again.

Probably, one of the important things is to inform patients in a way that gives them the confidence about the methods they use. I think with all the studies and science we can show that birth control methods we were talking about really protect against pregnancy, so that women can rely on them and enjoy sexuality without having the fear of getting pregnant. I think also the fact that women talk with each other and inform each other and those who use these effective methods very rarely tell other women: “I had a failure.”

The communication among users is important. Fortunately, very few have failures. Are your users reporting that they are still afraid of getting pregnant?

Probably, that is different in various countries. I have the impression that in Central Europe where I work this is not too much of a concern. Women know from their own experience over many years that these modern methods are effective.

Right. But there, I think, we should do more public work and ensure women that it is really effective.

I think we should really make people aware and inform people about the hormones used for contraception. Many people believe the hormones are dangerous per se, almost like a chemical poison.

But this is not the reality. The hormones used in birth control are actually adaptations of the body hormones, it’s a sort of body language. What we are trying to do is to give signals to the body that you don’t need to reproduce because you are already «pregnant» — it’s like a low-level pregnancy.

In the last 60–70 years we have collected a lot of information about birth control pills and we can now state — and this is general agreement all over the world, also from the authorities — that the benefit of birth control pills, of hormonal contraception, is much higher than the risk.

The biggest birth control benefit is effective protection against pregnancy. Pregnancy can be very dangerous. Hormonal contraceptives protect against ovarian and endometrial cancer, they’re good for osteoporosis, they treat endometriosis pain, dysmenorrhea, algomenorrhea. They’re good for the skin. A whole list of good things.

We also, of course, know about risks. We know that there is a small increase in thromboembolic risk, you might get a blood clot. But this refers to about 3 to 4 women per 10,000 cases and this usually occurs right during the first year of use. We have become better at detecting those women who have additional risks and discouraging them from taking the pill. We are looking into family history, blood thrombophilia and other risk factors. We also have to exclude women who are overweight, who smoke too much. 

A big discussion is about breast cancer — women are concerned about it. It looks like there is a small increase in breast cancer risk while taking the pill in the women of reproductive age. But the basic knowledge which we have now is that the pill itself doesn't cause breast cancer, but in those women where breast cancer is developing these hormones may accelerate it. It is also important that the risk is not lifelong. When you stop, it goes back to basic risk. 

In the end, when you take the pill there is a small risk of thromboembolic complications and even a smaller risk of breast cancer. They’re real, but for the large majority  (for 99 990 of 100 000 women) hormonal contraceptives are safe.

Don’t forget to check out the second part of our interview with prof. Johannes Bitzer here.

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