Whether or not a small fibroid affects menstruation is related to the location of its growth. Uterine fibroids are divided into submucosal fibroids, interstitial fibroids, and subplasmic fibroids according to their location. The details are as follows: 1) submucosal fibroids: even if they are small, they can affect menstruation, leading to increased menstruation and prolonged periods; 2) interstitial fibroids: if they grow close to the endometrium, they can affect menstruation, but if they are far from the endometrium, they usually do not affect menstruation; 3) subplasma fibroids: they have no effect on menstruation.