Scientists have spotted an elevated risk of stroke in women who became pregnant after fertility treatments.
Although the absolute number of strokes reported in the new study were low, women seeking fertility treatment should be made aware of the increased risk, said senior study author, Dr. Cande Ananth, chief of epidemiology and biostatistics at the Robert Wood Johnson Medical School in New Jersey.
Ananth offered possible explanations for the link, including that infertility procedures can cause physiological changes because women receive large amounts of estrogen during the treatments. This can lead to increased clotting, which is a strong risk factor for stroke.
“We know that women who receive infertility treatment have certain vascular complications, typically an increased risk of preeclampsia and placental abruption,” Ananth told the New York Times.
“People who receive the treatment receive it for a reason. Perhaps there are different biological characteristics,” among women seeking treatment, Ananth added.
In the study, researchers analyzed the cases of 31 million patients who had a hospital delivery between 2010 and 2018 in 28 states. This included more than 287,000 women who had infertility treatments.
They found that women who had undergone the treatments faced twice the risk of bleeding in the brain, known as hemorrhagic stroke. They also had 55% greater risk of ischemic stroke, when blood supply to the brain stops.
About 37 women were hospitalized for stroke for every 100,000 women who had fertility treatment.
About 2% of U.S. births involved fertility treatments, such as intrauterine insemination, assisted reproductive technology, use of a surrogate and fertility preservation procedures.
Some studies have linked the treatments to increased risks during a pregnancy, though they are generally considered safe, the Times reported.
While this study, published Aug. 30 in the journal JAMA Network, found these risks, another study of women in Scandinavian countries published earlier this month in the journal JAMA Cardiology did not. That study included 2.4 million women.