Fibroids are benign tumors. Only rarely will they become malignant. They can be located just under the lining of the uterine cavity (submucosal), deep in the muscle of the uterus (intramural) or near the outside of the uterus (subserosal). They can also be on stalks inside the uterine cavity (polypoid) or outside the uterus (pedunculated). They can be single or multiple, big or small. Some cause symptoms and some don’t.
Not everyone with fibroids has problems getting pregnant. About 2% of women with unexplained infertility have fibroids as the only cause found. It seems that the fibroids that are just under the lining of the uterine cavity (sub mucous) and inside the uterine cavity(polypoid)can cause infertility. The submucous fibroids and the polypoid may act like an IUCD, and may lead to infertility. Large fibroids may narrow the uterine cavity and lead to miscarriage or infertility. Fibroids can interfere with embryo implantation or predispose early miscarriages. Fibroids have a tendency to grow during pregnancy and may cause deformity of the arms and legs of the baby if they press on the fetus.