Fibroid Tumors in Uterus: Their Effect on Fertility
The uterus is composed of a thick layer of smooth muscle (myometrium) surrounding a thin lining (the endometrium) into which the embryo implants and which serves to protect and nourish a growing pregnancy. Approximately 20-40% of all reproductive age women will develop benign growths of the myometrium, referred to as fibroid tumors (leimomyata). These tumors are rarely malignant (see below). They can be located in the wall of the uterus (intramural), on the outside of the uterus (subserosal), within the uterine cavity (submucosal), on a thin stalk (pedunculated) or a combination of the above. Estrogen causes them to grow. African and African American women seem to have a much higher incidence of fibroid tumors. In fact, while fibroids are very rarely detected in young Caucasian women, it is quite common to find these tumors in twenty to thirty year old African and African American women.
Fibroid tumors, even large ones, can occur without producing any symptoms at all. However they can also cause a variety of symptoms depending on their size, location and the absence or presence of complications such as torsion (twisting) or degeneration (such as might occur when a fibroid grows so fast that it starts running out of its blood supply). The most common symptoms are heavy cyclical menstrual bleeding (menorrhagia) accompanied by menstrual pain (dysmenorrhea). Sometimes, especially when a fibroid protrudes into the uterine cavity, it can cause erosion of the endometrial lining and produce irregular or continuous bleeding (menomettrorhagia).
Sustained non-menstrual pelvic pain may point to torsion of a pedunculated fibroid that is attached to the inner or outer wall of the uterus, or to degeneration. Other possible symptoms include pain with deep penetration during intercourse (deep dyspareunia), bladder irritability, rectal pressure, constipation and painful bowel movements (dyschezia).
For the most part, only those fibroids that impinge upon the uterine (endometrial) cavity (submucosal) affect fertility. Exceptions include large fibroids in the muscle wall of the uterus (intramural) that can block the openings of the fallopian tubes as they enter the uterus, and where multiple fibroids cause abnormal uterine contraction patterns.
Surgery to remove fibroids (myomectomy) can also affect fertility in several ways. If the endometrial cavity is entered during the surgery, there is a possibility of post adhesions forming within the uterine cavity. This should always be checked by the performance of a hysteroscopy or through a fluid ultrasound (sonohysterogram), prior to beginning fertility treatment. Because myomectomy can be bloody, there is a high likelihood of post-operative abdominal adhesion formation, which could bind down or encase the ovaries, preventing the release of the eggs, or block the ends of the fallopian tubes. For this reason, it is important that myomectomies be formed only by accomplished surgeons, who are familiar with techniques to limit blood loss and prevent adhesion formation.
In some cases multiple uterine fibroids may so deprive the uterine lining (endometrium) of blood flow, that the delivery of estrogen to the endometrium is curtailed to the point that the lining cannot thicken sufficient to support a pregnancy. This can result in early 1st trimester (prior to the 13th week of pregnancy) miscarriages. Large or multiple fibroids, by curtailing the ability of the uterus to stretch in order to accommodate the spatial needs of a rapidly growing pregnancy, may precipitate 2nd trimester (beyond the 13th week) miscarriages and/or trigger the onset of premature labor.
Sizable fibroid tumors are usually easily identified by simple vaginal examination. However, even the smallest fibroid can be identified by transvaginal ultrasound. Sometimes it is difficult to tell if the fibroid is impinging on the uterine cavity. In such cases, a hysteroscopy (where a telescope like instrument, inserted via the vagina into the uterine cavity) or a sonohysterogram where injected fluid, distends the uterine cavity allowing for examination of its inner configuration can help distinguish between intramural and submucosal fibroids. Magnetic Resonance Imaging (MRI) can also be used to distinguish between fibroid tumors and another condition that also involves affects the uterine muscular wall, known as adenomyosis. This condition is characterized by endometrial tissue growing deeply into the uterine wall.. Given the often-diffuse nature of adenomyosis, it can be very difficult to remove surgically. This contrasts with fibroid tumors, which are well defined and are usually easily removed.
Surgical Treatment: The mainstay for the treatment of fibroid tumors is surgical removal (myomectomy). Small, asymptomatic fibroids that do not impinge upon the endometrial cavity will usually not require treatment other than observation and vigilance. Large fibroids and submucosal fibroids should be removed prior to starting fertility treatments such as In Vitro Fertilization (IVF) in order to decrease the chance of implantation failure, miscarriage, pregnancy complications and premature labor. Intramural and subserosal fibroids are readily removable by laparoscopic resection or via an abdominal incision. The former allows for a more rapid convalescence and is ideal for the removal of small and accessible superficial fibroid tumors, while the latter approach is preferred for treating larger and less accessible fibroids.
Regardless of whether the laparoscopic or abdominal approach is employed, adequate closure of the uterine wall is essential in order to reduce the subsequent risk of uterine rupture during pregnancy or labor. This is one of the main arguments used against the use of laparoscopic removal of large, multiple or remotely situated fibroids. While laparoscopic myomectomy requires but a few days (at most) for post-operative convalescence, abdominal myomectomy usually requires 6-8 weeks of recovery time. When myomectomy necessitates or results in the uterine cavity being entered (purposefully or inadvertently), it should always be followed up with a “2nd look” hysteroscopy to rule out scar tissue formation, which occurs frequently in the presence of submucosal fibroids.
Uterine polyps (and in some cases, also submucosal fibroids), can often be removed hysteroscopically (through the vagina). This eliminates the need for abdominal surgery and greatly reduces the recovery time. Hysteroscopic surgery is only useful if the majority of the fibroid protrudes into the endometrial cavity, ensuring that the tumor defect will not be too large. This surgery is often done under laparoscopic guidance, to reduce the risk of uterine perforation. After hysteroscopic surgery it is often advisable to prescribe cyclical hormonal therapy for a few moths to encourage regeneration of the endometrial lining over the area of tumor defect and healing of the uterine muscle. A 2nd look hysteroscopy should be performed a few months later in all cases, to rule out scar tissue formation even if it means delaying or deferring the initiation of definitive fertility treatment.
Medical Treatment: The growth of fibroid tumors is estrogen-dependent. Thus when a woman enters menopause and stops making female hormones, fibroids tend to shrink in size on their own. Conditions that mimic menopause can also reduce the size of fibroid tumors. The most common of theses treatment is with a medication such as lupreulide acetate (Lupron), which shuts off the communication of the brain with the ovaries, preventing hormone production. However, this type of medication can only be taken for a limited period (usually 6 months) and once the medication is stopped the fibroids will usually regain their original size within a few months. The medication is therefore only a “temporary fix,” used mostly to decrease the size of large fibroids in order to make their ultimate surgical removal easier, or to help a woman bridge the gap until spontaneous menopause sets in. For the majority of women there is no major benefit from Lupron therapy prior to surgery.
Embolization of Fibroid Tumors: Myomectomy always carries the small (although infrequent) risk that severe, uncontrollable intra-operative bleeding could require the performance of a hysterectomy (complete removal of the uterus) as a life saving measure. Moreover, some women are poor candidates for surgery. This is where a new procedure known as embolization comes in. Embolization is a procedure in which small particles are injected into the arteries of the uterus under radiological guidance to shut off the blood supply to the fibroids, in the hope that they will “shrink” and perhaps, even disappear.
Embolization is relatively new to the field of gynecology and little is known about its potential effects on future fertility. We are concerned that in the process of shutting off the blood supply to the uterus, it will permanently so reduce endometrial blood flow, as to compromise embryo implantation. For this reason, I do not currently recommend this therapy for women who still wish to conceive and carry a baby in their uterus. At present, it seems best suited for symptomatic women who are finished with their childbearing or who are planning to use a gestational surrogate.
Malignant Change in Fibroid Tumors:Fibroids rarely undergo malignant change. The reported incidence is less than 1 in 2000 cases. Fibroids usually grow very slowly (over a number of years). However, when growth occurs rapidly over a month or two, especially in older women who have large fibroids, it should raise the suspicion of this very rare but extremely serious complication.