An important question to answer in any field of medicine is whether treatment will increase the chance for health problems in our patients. In the infertility field, there are three questions:
- Are infertility patients at greater risk for health problems?
- Do fertility treatments increase the risk for health problems?
- Is there a difference in the risk for health problems depending on whether the treatment is successful?
A recent study from a Canadian medical journal has tried to answer some of these questions.
The INFERTILE study (Investigation of Notable Failed Endeavours at Reproductive Treatment and Ischemic Long-term Events looked at whether fertility therapy failure is associated with subsequent adverse cardiovascular events. Cardiovascular events are things like strokes, heart attacks and blood clots. This study followed over 28,000 women who received fertility treatment in Ontario Canada between 1993 and 2011.
What did the study show?
The study found that women who took injections of fertility medications and failed to deliver a baby had a higher rate of cardiovascular events over the next several years compared to women who took injections and did not deliver a baby. Overall, the annual rate of cardiovascular events was 19% higher among women who did not give birth after fertility therapy than among those who did.
Does this mean that fertility treatments caused these problems?
Probably not. The study did not include infertile women who did not take fertility medications. That is a group you would need to study in order to determine whether the medication treatment itself was responsible. What this study showed is that women who did not deliver a baby had a greater risk than those who did.
The reasons for this are not clear but it may be that failure to achieve pregnancy is a way to identify women who were already at higher risk of developing these problems. We know, for example, that men who have chest pain or EKG changes when running on a treadmill are more likely to have cardiovascular events. This is known as a “stress test”. In this case, failure to become pregnant after fertility treatment might be a stress test that predicts women who will be more likely to develop cardiovascular problems.
Some evidence to support this interpretation comes from looking at some of the characteristics of these women BEFORE they started fertility treatment. The women who failed to deliver a baby were more likely to be obese, smoke cigarettes and have high cholesterol. All of these are known risk factors for cardiovascular disease.
What should I do?
All women should be aware of the risk factors for cardiovascular disease. If you have risk factors, you should work with your primary physician to try to modify or reduce those risk factors.
Failure of fertility therapy and subsequent adverse cardiovascular events. Jacob A. Udell MD MPH, Hong Lu PhD, Donald A. Redelmeier MD MSHSR CMAJ 2017 March 13;189:E391-7. doi: 10.1503/cmaj.160744