Q&A: How dangerous are fibroid tumors in pregnancy?

A fibroid "tumor," in spite of such a name, is merely a benign overgrowth of fibrous tissue in the uterus (womb). The official name is leiomyoma (pl. leiomyomata). Fibroid tumors occupy space. In the uterus, which depends on the muscular layer to contract, this waste of space leaves the whole muscular unit less efficient. If the fibroid is big enough, it can interfere with labor during pregnancy, or it can lead to excessive bleeding during periods when not pregnant. But is it dangerous?

In pregnancy, it can act as a foreign body, making a pregnant woman more prone to premature labor. It can bulge toward the baby, causing the baby to seek comfort in a breech or other abnormal position, increasing the risk of needing a C-section. Like a malignancy, it can outgrow its own blood supply, leading to its death which, ironically, is NOT a good thing. Dead tissue is very inflammatory and can even cause peritonitis, which would be a really revolting development in a pregnancy. Also, its size could compress the ureters (tubes carrying urine from the kidneys to the bladder), causing a back-up. This is already happening with pregnancy to some extent, and the extra compression could cause kidney infection or other complications.

Can anything be done?

Not really. Not until after the pregnancy. Unless of course there's the rare but serious complication of a degenerating fibroid and associated peritonitis. I emphasize that this is rare. It requires surgery, and I haven't had to do a pregnant myomectomy (removal of a fibroid) in twenty years. If a fibroid is painful during pregnancy, an ultrasound can usually show some central necrosis (tissue death) in a fibroid. But for the most part, it needs to be left alone.