How fast does an aneurysm grow?

How Fast Does an Aneurysm Grow?

Most aortic aneurysms grow at a slow and predictable pace—usually between 1 to 3 millimeters per year. For many people, this means that once an aneurysm is detected, doctors can monitor it closely over time rather than rushing into treatment.

However, the growth isn’t always linear. As an aneurysm gets larger, the wall of the aorta becomes weaker, and the pressure inside increases. This creates a feedback loop where the larger the aneurysm, the faster it tends to expand. That’s why size matters so much: an aneurysm that’s already several centimeters wide is not only more dangerous but also more likely to grow at an accelerated rate.

Regular imaging scans—like ultrasounds or CT scans—are key in tracking this progression. For smaller aneurysms, check-ups every 6 to 12 months are common. Once the diameter reaches a critical threshold (often around 5.5 cm in men, 5 cm in women), surgical repair is usually recommended to prevent rupture.

Several factors can influence growth speed: high blood pressure, smoking, age, and genetics all play a role. Quitting smoking and controlling blood pressure are among the most effective steps to slow progression. While an aneurysm may seem like a silent condition, its slow creep can turn serious if ignored. That’s why early detection and consistent monitoring are so important.

It’s also worth noting that rapid growth—more than 5 mm per year—is uncommon but a red flag. In such cases, doctors may act sooner, regardless of overall size, due to the increased risk.

Understanding the timeline and triggers of aneurysm growth helps patients and physicians make informed decisions—balancing watchful waiting with timely intervention.