For women struggling to conceive, IVF, or in vitro fertilization, is often considered a safe alternative to traditional methods of conception. But a new study has found that IVF treatment may slightly increase a woman's risk for pulmonary embolisms and blood clots during pregnancy.

The study comes from researchers at the Karolinska Institute in Sweden who evaluated 20,000 women who gave birth after conceiving via IVF and 100,000 women who gave birth around the same time after conceiving "naturally." Researchers found that pulmonary embolisms – blood clots in the lungs – and venous thromboembolism - blood clots in the veins - occurred more frequently in women who conceived through IVF, particularly in the first trimester of pregnancy.

Still, the overall risk for any type of blood clot was relatively low. Overall, a woman's risk of experiencing a pulmonary embolism during pregnancy is 0.06 percent. The risk increased to 0.08 percent for women who conceived through IVF. But pulmonary embolisms are also the leading cause of maternity-related deaths for women in the U.S., so even a slightly higher risk is worth noting.

Researchers hope that by identifying this greater risk, doctors will be more apt to talk to their patients about the symptoms of blood clots and pulmonary embolisms so that they can intervene early if necessary.

The study was published this week in the British Medical Journal.

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