Fibroids and Pregnancy

Most fibroids do not get in the way of a pregnancy however, some fibroids in certain areas, can make conception difficult or lead to miscarriage. 

Fibroids can be associated with a range of reproductive dysfunction including recurrent miscarriage, infertility, premature labor, fetal malpresentations and complications of labor. These complications most often occur when fibroids physically distort the uterine cavity. Fibroids may press against, or block the entrance to, the fallopian tubes, thus preventing the egg from reaching the uterus. Women who have recurrent miscarriages may have a submucous fibroid which is growing inwards into the womb consequently causing the miscarriage. It is less clear whether fibroids in the wall of the uterus cause reproductive problems. 

Women with large or symptomatic fibroids may choose to undergo an assessment of the uterine cavity (hysterosalpingograpy or hysteroscope) before attempting pregnancy. If fibroids are detected on the inside of the uterus (submucous fibroids) and distort the uterine lining, they are a significant cause of reproductive problems and should be removed.

A fibroid can also interfere with labor and birth if it blocks the passage to the birth canal. If this is the case, your doctor may recommend a Caesarean section. Fibroids may increase your risk of bleeding heavily after birth, and can increase the time it takes for your womb to return to its normal size.

Just as fibroids can affect pregnancy, pregnancy can affect fibroids. It is thought that fibroids grow during pregnancy because of higher levels of estrogen; however there is little evidence to support this.

Another effect of pregnancy on fibroids is a process called 'red degeneration.' This is when a fibroid’s blood supply is cut off, causing it to turn red and die. Red degeneration can cause intense abdominal pains and contractions of the womb, which could lead to early labor or miscarriage. The pain and contractions usually stop on their own but your doctor may give you drugs to ease the pain and stop the contractions more quickly.

Fibroids are never removed during a pregnancy because of the risk of bleeding (hemorrhage).