The most common risk factor of breast implant surgery is capsular contracture. But surprisingly, it's not the most common reason that women replace their implants. Neither is rupture. In fact, the things women may worry about leading up to the decision to get implants (and the risks that get publicized) aren't even in the top two, says Grant Stevens, MD, FACS, medical director of Marina Plastic Surgery in Marina del Rey, CA. In his practice, here are the top four reasons women seek to replace implants.

1. Size Change

Size is the number one reason women replace their breast implants. "They come to me and they say, 'I want them a little larger,'" Dr. Stevens says. When women initially make the decision to have implants, size is often their number one concern. After all, the reason they're seeking implants is that they want to have larger breasts to be able to wear the clothes they want and feel more confident. But it can be hard to envision the change — not just what they will look like (new technology can help give them a picture of that), but also, what it will feel like to have larger breasts. But after a woman has breast implants for a while, she becomes used to it — and often, she feels that pang of "I wish I would have gone bigger." She's not dissatisfied with breast implants, she's just dissatisfied with the size.

2. Saline to Silicone

From 1992 until 2006, there was a moratorium on silicone breast implants. There were exceptions, and certain groups of women could still receive silicone implants. But the vast majority of women had to settle for saline. Now that the safety of silicone has been established (they've been extensively studied), the United States is moving back toward silicone. The rest of the world already uses mostly silicone (only two percent of the implants used worldwide are saline, Dr. Stevens says). "Now, about half of the implants we use in the U.S. are silicone, but that number is growing," he says. Many women who got saline implants under the moratorium have been dissatisfied with their saline implants, and they are now coming back and opting for silicone, which looks and feels more like a woman's natural breast.

3. Capsular Contracture

As aforementioned, capsular contracture (when the area around the implant starts to squeeze the implant, causing pain, implant distortion, and asymmetry), is the most common risk of breast implant surgery. Dr. Stevens' latest study shows that it happens to about three percent of breast implant patients. There are treatments for capsular contracture, but quite often, the implant will need to be replaced. The good news is that capsular contracture is specific to the implant — it doesn't do lasting damage.

4. Infection

Number four on the list is infection. Infection can happen for any number of reasons (infection is a general risk of any type of surgery). That's why you're given antibiotics during surgery (and mostly likely, after). While infection of breast implants isn't that common, it can happen. Your doctor will continue to treat the infection, but sometimes it requires that the implant be removed. After the infection is completely gone and your body has healed, you can get the implant replaced.