Stroke: Fertility treatment linked to higher risk

Evan Walker
Evan Walker TheMediTary.Com |
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Experts say you should consult with a doctor before undergoing any fertility treatments. Maskot/Getty Images
  • Stroke is one of the leading causes of maternal mortality in the United States.
  • A large retrospective study found that people who received fertility treatments were more likely to be hospitalized for stroke in the 12 months following delivery.
  • The absolute risks of being hospitalized for stroke are still low, whether you receive fertility treatments or not.

People who receive fertility treatments might have a higher risk of stroke as well as hospitalization from a stroke within a year after delivery than those who did not receive such treatments, a new study suggests.

The findings come from a new retrospective study of more than 31 million pregnant women ages 15 to 54 and conducted by researchers at the Rutgers Robert Wood Johnson Medical School in New Jersey.

All told, pregnant people who received fertility treatments were 66% more likely (affecting 8 in 100,000 pregnant people) to be hospitalized for a stroke within 12 months of delivery compared to those who delivered after spontaneous conception.

More significantly, the researchers said, the risk for potentially life-threatening hemorrhagic stroke (bleeding in the brain) was more than twice as high for people who had fertility treatments while the risk of ischemic stroke (blood clot in the brain) was 55% higher.

“Strikingly, the increase in risk was evident even as early as the first 30 days post-delivery, which highlights the need for early and continued follow-up in this population,” the study authors wrote.

The findings are particularly significant since almost 6% of all pregnancy-related deaths in the United States are a result of stroke.

That said, hospitalization for stroke after pregnancy is still relatively rare, at a rate of 37 hospitalizations per 100,000 for those who received fertility treatments and 29 hospitalizations per 100,000 people for those who didn’t receive fertility treatments.

The researchers proposed three separate theories as to why fertility treatments might be associated with increased stroke risk, including pre-existing conditions. However, exploring those avenues was outside of the scope of the study.

Although people with any hospitalizations with cardiovascular disease (CVD) before or during delivery were excluded from the study, that was the extent of any CVD-related exceptions from the data set.

And that’s why people shouldn’t rush to worry, said Dr. Alex Robles of the Columbia University Fertility Center in New York.

“These data are difficult to extrapolate to individual patients as no pre-pregnancy or inter-pregnancy comorbid conditions were reported,” he told Medical News Today. “It’s possible that some of these patients had pre-existing high-risk conditions such as pre-pregnancy hypertension, diabetes, or obesity, all risk factors for stroke. In addition, it is also possible that the fertility cohort was a higher risk group at baseline, as advanced maternal age predisposed patients to develop some of these conditions during pregnancy.”

Dr. Sahar Wertheimer, a reproductive endocrinologist at HRC Fertility in Southern California, agreed.

“I find it a compelling study because we do think of elevated estrogen levels (inherent in IVF) as a risk factor for stroke and we do know that IVF [in vitro fertilization] causes increased vascular risks during pregnancy,” she told Medical News Today. “However, drawing the conclusion that infertility treatment causes strokes and not that perhaps women with infertility are predisposed to strokes for the same underlying causes as their infertility is a dangerous conclusion. For example, I did not see a family history included in the baseline demographics.”

Wertheimer also noted that the study didn’t differentiate between different types of fertility treatment and could therefore not separate the relative risks of each.

She also noted that the absolute risks reported in the study were still small enough that they shouldn’t necessarily discourage hopeful parents.

“People should be aware of the increased risks of IVF in general, including the slightly higher risks posed to the pregnancy,” Wertheimer said. “But everything in medicine is risk versus benefit. Fertility treatments allow couples with infertility to have the most amazing life-changing results.”

While typically advanced maternal age is thought to be an increased risk factor for stroke, studies have shown that being pregnant presents a significantly higher risk for stroke even among younger people.

So when in doubt, experts say the best move might be to get evaluated when you’re pregnant, especially if you have a family history of cardiovascular disease or other risk factors.

“This is why at Columbia University Fertility Center, we always require a maternal fetal medicine doctor consultation and evaluation for any patient who may be ‘high risk,’” Robles said. “This evaluation may help identify patients who need closer monitoring or may be deemed as unsuitable candidates for pregnancy.”

“In general, fertility treatments are very safe and most patients tolerate it well,” he added. “However, it is important to get a thorough consultation from a trained reproductive endocrinologist to evaluate your risk and candidacy to undergo such treatments.”

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