Uterine Fibroids (Leiomyomas)

Uterine fibroids (leiomyomas) are noncancerous growths of muscle tissue in the wall of the uterus. Clinicians classify fibroids by location with the FIGO system (types 0 through 8). The location of a fibroid shapes its effect on fertility.¹ Fibroids are very common in women of reproductive age. Some cause no problems. Others can prevent an embryo from implanting or lead to pregnancy loss. Size, number, and distance from the uterine lining all matter.

Submucosal fibroids (FIGO types 0 through 2) bulge into the uterine cavity. They carry the greatest burden on fertility. They alter blood flow to the lining and change the surface where an embryo implants. They also make it harder for a pregnancy to continue.¹ Intramural fibroids lie within the muscle wall. They can also lower the chance of conception and raise the risk of miscarriage. This effect can occur even when the uterine cavity keeps its normal shape. The evidence here is less consistent than for fibroids inside the cavity.² Large intramural fibroids can also press on the part of the fallopian tube that passes through the uterine wall. Subserosal fibroids lie on the outer surface of the uterus. They have the least direct effect on implantation. Large subserosal fibroids can still limit the movement of the tubes or add to pelvic pain.

Myomectomy, surgery that removes fibroids and preserves the uterus, is the standard restorative option when fibroids contribute to the problem. The surgical approach depends on location. For fibroids that reach into the cavity, surgeons use operative hysteroscopy through the cervix. Fibroids in the wall or on the surface require operative laparoscopy or a small open incision. The choice depends on their size and depth. The goal is to restore the normal shape of the uterus before infertility or pregnancy loss is attributed to other causes.