I have one but it wasn't mentioned on the US I got. They are caused by low progesterone/estrogen dominance, hence why they can also be in tandem with infertility or endometriosis - all have the same cause. It is also why they can shrink or remain dormant during pregnancy, due to the high progesterone. They also disappear usually during menopause with the drop of estrogen. Estrogen is a growth hormone, certain cysts, fiboids, cancers, et al, they are all promoted with estrogen. I am worried my baby may have implanted on the fibroid or my c-scar, but neither has been mentioned yet.