 It's almost like you need to have a perfect storm. So if you have zero family history of fibroids, you're unlikely to start growing them as early as you would. So you just might be one of that 70% of women who just happens to grow a fibroid because she has a uterus and it's been around for a while. Those are usually the asymptomatic kind. Nearly half of all fibroids don't cause any symptoms at all, hence why many women never realize they're there in the first place. Even Williams was surprised to find out that she had developed a small fibroid.