Women who do not become pregnant after fertility treatment may be at greater risk of cardiovascular events, a new study finds.
Researchers found that women who did not become pregnant after undergoing gonadotropin-based fertility therapy - treatment often used in preparation for in vitro fertilization (IVF) and other assisted reproductive technologies - were at greater risk of heart failure and stroke than those whose fertility therapy was successful.
The research team - led by Dr. Jacob Udell of the Clinical Evaluative Sciences (ICES), the Peter Munk Cardiac Centre, and Women's College Hospital in Canada - notes that previous studies have suggested a link between fertility therapy and a short-term risk of cardiovascular events.
However, the researchers say that few studies have assessed the long-term impact of fertility therapy on heart health, especially among women whose fertility treatments have been unsuccessful.
"Failure of fertility therapy may be an early indicator of future cardiovascular risk by acting as a unique cardiometabolic stress test," says the authors. "In addition, fertility therapy may lead to adverse cardiovascular events by inducing background thrombosis, activating the renin-angiotensin system or inducing vascular injury from ovarian hyperstimulation."
To investigate how fertility treatment failure affects women's long-term heart health, the researchers reviewed the data of 28,442 women of an average age of 35.
All women had undergone gonadotropin-based fertility therapy in Ontario, Canada, between April 1993 and March 2011, and they were followed until March 2015. The women had an average of three fertility treatments.
Cardiovascular event risk 19 percent higher with fertility therapy failure
A total of 9,349 of the women gave birth within a year of undergoing fertility treatment. For the remaining women, fertility therapy was unsuccessful.
Over an average 8.4 years of follow-up, 2,686 cardiovascular events were identified.
Compared with women who gave birth following fertility therapy, women who did not become pregnant after fertility treatment were found to have a 19 percent greater risk of cardiovascular events, particularly stroke and heart failure.
However, the team points out that the absolute risk of cardiovascular events was modest for women who did not become pregnant after fertility therapy, at 10 cardiovascular events per 1,000 women over 10 years.
In comparison, there were 6 cardiovascular events per 1,000 women over 10 years for those who gave birth after fertility therapy.
Still, the researchers say that their findings indicate that fertility therapy might be a risk factor for cardiovascular disease among women, and this association warrants further investigation.
Furthermore, the team believes that women who have undergone fertility therapy should consider how the treatment might have impacted their heart health.
"We don't want to alarm women who undergo fertility therapy; we are instead suggesting that as women age, they should stay mindful of their health and remind their physician about any fertility therapy years earlier. It can be an opportunity for their doctor to review other risk factors for heart disease and discuss ways to protect against future cardiac problems."
Study co-author Dr. Donald Redelmeier, ICES
The researchers warn that there are some limitations to their study. For example, it did not include less invasive forms of fertility treatment.