The Benefits and Risks of COCs and POCs

Michael J. Bloch, MD

In this video, Michael J. Bloch, MD, discusses the link between combined oral contraceptives and increased risk of arterial thrombosis, the risk of venous thromboembolic disease, and alternative contraceptives available for at risk populations. 

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Michael J. Bloch: My name is Dr Michael Bloch. I am a vascular medicine specialist from Reno, Nevada.

The vast majority of women who are overweight or obese can take combined oral contraceptives without much increase in risk. It is just a population that we think about a little bit more. Women who are overweight and obese do have a higher incidence of cardiovascular risk factors, a slightly higher risk of venous thromboembolic disease, and tend to have a little bit higher blood pressure. As we mentioned in an earlier video, those women who do have cardiovascular risk factors or risk for venous thromboembolic disease or high blood pressure are just a little bit more likely to have negative or adverse effects from COCs. It is just a population that I would say we just take a pause and think about that risk just a little bit more deeply before we prescribe a COC. That is, I think, pretty well established in the WHO and the CDC guidelines around this. The vast majority of overweight and obese women, that decision-making will be, yes. I think this is a safe and effective form of contraception for you. But it does give us an opportunity to have that discussion about and perhaps look for other cardiovascular risk factors in those women.

As I mentioned in an earlier video, the physiological effects of estrogen are profound on cardiovascular structure and function. As a hormone, it exerts multiple different effects. Some of those may be beneficial. Some of those may be more adverse. It is really that balance of physiologic effects that contribute to the risk of these agents in some women. We do know that there is an increased risk of thrombogenesis with use of estrogen-containing oral contraceptives. In most patients, that risk, although it is higher if you are taking a COC, the baseline risk is so low that we do not worry about it very much. But in women who do have multiple cardiovascular risk factors or women who are older and smoke, we do think a little bit about perhaps we should look for a different form of contraception given that risk of arterial thrombosis leading to stroke and heart attack.

That is why I think where the risk is probably the most carefully studied. We know that use of estrogen-containing oral contraceptives increases the risk of DVT and PE between about four and sevenfold as compared to women who use other forms of contraception. That risk is definitely high. Now, it is a low baseline risk. We are taking a low number and increasing it by four to seven times. Once again, the vast majority of women are at low risk of venous thromboembolic disease. There is this perfectly safe form of contraception for them. But if we do have women who have a previous history of DVT or PE, even some who have a family history of DVT or PE, patients who have a known thrombophilia or who have cancer, that increased level of risk may make COCs not an appropriate choice for those women.

I run a large anticoagulation clinic. We get asked this quite a bit. One of the things that we try to really communicate to women is that pregnancy is also a risk for DVT and PE. If you do have a woman who is at risk for DVT and PE, they need to think about their contraception because we do not want to see unplanned pregnancies in those women. Finding another suitable form of contraception is really important. Progestin-only contraception is definitely safer. Whether there is some increased risk with progesterone-only, contraception is a little bit controversial. We will offer it to some women. But in general, we would like to offer women who are at increased risk of venous thromboembolic disease non-hormonal contraception. Plenty of options that are available at this point.

Yeah. I think the answer is really in your question. I think that when we are at our best in speaking to women about contraception, we are talking about not something you can do or cannot do but weighing alternatives, so talking about the risks as well as the benefits, and then allowing a woman to be involved in that choice, making sure they understand all the options, making sure they understand the risks and benefits of all those options and then can make an informed choice with shared decision-making with their provider. I think that one of the things that... We are often in a rush in our office. We want women to do what we are seeing: to decide right now. I would say that is something that we have tried to institute in our practice, is really giving women some information and time to think about it and making them a follow-up appointment to come back and be able to express their opinion maybe after they have educated themselves a little bit more because there are a ton of great resources out there for women.

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