Fibroids can affect fertility more commonly than once thought and frequently co-exist in many patients with the diagnosis of infertility. The types of fibroids most likely to cause reproductive problems are large fibroids (diameter greater than 4 centimeters) or those that are located inside the uterine cavity regardless of their size. Because every case is different, women who have fibroids and would like to become pregnant should discuss this with their obstetrician-gynecologist and in complicated cases with a fertility specialist to determine the best approach for management.
What Are Fibroids?
Fibroids are non-cancerous muscular growths and they come in all sizes. Some are smaller than a pea while others are much larger. As one might expect, it’s the larger ones that are most likely to cause problems, sometimes distorting the entire uterus, but even smaller ones that are inside the uterine cavity can cause implantation failure and infertility.
Fibroids of the uterus (womb) can be found by a doctor during a routine pelvic exam or a pelvic ultrasound. Uterine fibroids have been found in about 20% of all women of reproductive age. Most cause no problems and require no treatment. For those that do cause problems, there are many different treatment options.
How Fibroids Affect Fertility
There are three types of uterine fibroids, those located inside the wall of the uterus (intramural), those located in the outer wall of the uterus (subserosal) and those protruding into the uterine cavity (submucosal). To better understand these locations, see the diagram.
Though they’re the least common type, fibroids that protrude into the uterine cavity (submucosal) are the likeliest to impair fertility. They do this by a number of possible mechanisms:
- They can change the position or shape of the cervix (the neck of the womb), making it harder or impossible for sperm to travel from the vagina to the womb.
- They can block the fallopian tubes, preventing passage of the egg from the ovaries to the uterus.
- They can impede blood flow to the uterus and interfere with implantation of the embryo.
- They can cause changes in the uterine muscle that prevent normal movement of sperm or embryo.
- They can distort the endometrial cavity, cause bleeding and interfere with implantation.
- They can create a hostile environment and cause inflammation of the uterine wall.
Uterine fibroids can also grow during pregnancy and cause additional complications. Though these can be serious, the most common complication is pain, which usually responds to bedrest, hydration or over-the counter pain medications. Surgery is almost never done during pregnancy.
If fibroids are multiple and large, the risks of preterm labor, cesarean delivery, excessive bleeding after delivery, hospitalization due to severe pain and complications increase significantly and surgical removal may minimize such risks.
Treatment of fibroids for non-infertility population:
There are many different treatments for fibroids and type of treatment depends on many variables.
The most common is watchful waiting, meaning that that the condition is monitored regularly without any proactive treatment. This is the medical equivalent of the old adage “If it’s not broke, don’t fix it.” Watchful waiting is living with whatever symptoms fibroids are causing (if any) and waiting to see if there are any changes. Fibroids grow slowly–if at all–and tend to shrink after menopause.
MRI guided focal ultrasound, uterine artery embolization, ablation of the endometrium, subtotal or total hysterectomy can be treatment options for women who do not desire future fertility or those in the peri-menopausal years.
Many medications can offer short term relief. Birth control pills or progestins can lessen any excessive menstrual bleeding that fibroids are causing. Gonadotropin-releasing hormone agonists block estrogen and progesterone production, temporarily putting you in a postmenopausal state. This will usually shrink fibroids, but that only lasts while you’re taking the medication, which cannot be taken long term due to significant side effects.
Treatment of fibroids in patients with infertility and management prior to IVF:
Whereas fibroids are common in women undergoing infertility treatment, in most cases observation is sufficient enough during IVF treatment as well as throughout the pregnancy. If fibroids are symptomatic (i.e. pain, bleeding, pelvic pressure), inside the endometrial cavity (submucous) or inside the muscle layer (intramural) and pressing on the endometrial cavity, they should be surgically removed.
Evidence suggests that such fibroids may lower implantation and pregnancy rates and increase of having a miscarriage significantly. Removal of these fibroids significantly improves outcome, result in lower miscarriage risk and improve implantation as well as IVF success rates.