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Fertility treatment not linked to long-term cardiovascular risks, study finds

Aug. 2, 2013

By Patricia Nicholson

Women who have used fertility therapy to add to their families need not worry about the effects of those treatments on their long-term cardiovascular health. New research shows that fertility treatment is not associated with any excess cardiovascular risk later in life. In fact, mothers who conceived using fertility treatment had significantly lower cardiovascular risks than other mothers.

“It’s a reassuring finding,” says Dr. Jacob Udell, lead study author and a cardiologist at Women’s College Hospital (WCH). “We don’t need to sound any alarm bells, and that should reassure practitioners and patients.”

The research from WCH and the Institute for Clinical Evaluative Sciences (ICES) was published in the Journal of the American College of Cardiology.

As the researchers point out in the introduction to their study, the focus of fertility treatment is to get pregnant. Treatment decisions prioritize that short-term goal, not necessarily long-term health. However, there are some potential risks associated with fertility treatment.

“There are a lot of data to suggest that short-term fertility therapy has associated risks with blood clots, with high blood pressure in pregnancy, and with diabetes in pregnancy, all of which could lead to long-term cardiovascular disease,” says Dr. Udell. In the context of women delaying pregnancy until they are older and more at risk of developing heart disease, it becomes even more important to examine the potential long-term health risks of fertility treatment.

“Fertility therapy is being used more and more. Not only that, but in those women who need to use fertility therapy, sometimes you need to use it several times, for several cycles, before it’s successful,” Dr. Udell says. “No one had looked at this before: whether or not there were any long-lasting cardiovascular effects of fertility drugs in these women.”

Reassuring results

Dr. Udell and his colleagues looked at 1,186,753 women who gave birth in Ontario hospitals from 1993 to 2010. Of those women, 6,979 had received fertility treatment (such as intrauterine insemination, in-vitro fertilization (IVF), and other types of stimulated ovulation) in the two years before they delivered a baby. Over a median followup time of almost 10 years, the researchers tracked cardiovascular health by searching for deaths or hospitalizations from cardiovascular causes such as heart attack, heart failure or stroke.

The results did not reveal any excess cardiovascular risk among the women who underwent fertility therapy. In fact, those who had fertility treatments actually had 45 per cent lower cardiovascular risks than those who did not.

“Really surprisingly, there was a lower risk for death and for cardiovascular disease in those women who used fertility therapy, in fact it was almost half the risk. We found that very reassuring. We delved a little deeper and realized that these women were likely leading very healthy lifestyles after fertility therapy,” Dr. Udell says.

“There are plausible explanations for there potentially being some protective effect of the medicine, but more realistically, if you put in all the effort, time and, in our province, money – because it’s privately paid for most of the time – to invest in starting a family, those women are likely to protect their investment, we think, and lead healthier lifestyles thereafter.”

Those who underwent fertility therapy also had fewer episodes of depression and self-harm in the long term. There was no increased risk of breast or ovarian cancer in women who had fertility treatments.

The study did not include women who used fertility therapy but did not give birth.

“That’s our next planned study using ICES data. We did not look at them in this study and it’s one of the biggest elephants in the room,” Dr. Udell says, adding that women may undergo fertility treatment multiple times without a successful pregnancy. “It’s important to look at that group, and that’s our next study.”

Increased complications and risks

Although there were no long-term cardiovascular risks, it is important to note that women who underwent fertility therapy did have an increased incidence of pregnancy complications: a nearly 30 per cent increase in diabetes in pregnancy, a 16 per cent increase in placental disorders and a 10 per cent increase in pre-eclampsia. This is especially relevant given the marked increase in fertility treatments over the 17-year study period: from 1 in 400 births to about 1 in 80 births. Almost one per cent of deliveries in North America are now the results of fertility treatments.

The average age of women who received fertility treatment was 34, compared to 29 for those who did not. Older age is a cardiovascular risk factor, and women who had fertility therapy also had higher rates of other risk factors.

“Women going into fertility therapy were on average five years older than the general population getting pregnant, and also had established risk factors of high blood pressure, diabetes and obesity going into pregnancy,” Dr. Udell says. “Those are all known to be potential complications that could manifest with long-term risks. So the finding that they may be leading a healthy lifestyle is important.”

Dr. Udell says the research team hopes that the study draws attention to risk factors that may get overlooked after pregnancy.

“The obstetrician isn’t going to follow these women long-term after their pregnancy, and these women may not show up on the radar of a cardiologist until decades later. At Women’s College Hospital we advocate for a preventive cardiology approach, especially in women,” Dr. Udell says.

“I hope this is a call to those people who do notice that they have risk factors to get some preventive attention and care, either with their family doctor, with an internist or a cardiologist.”



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