Uterine leiomyomas and their clinical sequelae are a common gynecologic problem, as fibroids are present in approximately 25% of reproductive aged women.28
While leiomyomas may be asymptomatic, they can be associated with heavy menstrual bleeding, dysmenorrhea, pelvic pressure, and obstructive symptoms such as urinary frequency and constipation.29
Symptoms from leiomyomas may be managed with medical therapy, but they remain the most common indication for hysterectomy in the US.29
The uterine location of the myomas – subserosal, intramural or submucosal – effects the clinical sequelae. Subserosal locations are more commonly associated with obstructive symptoms, while submucosal are correlated with heavy menstrual bleeding.
The LNG-IUS has been studied in women with leiomyomas, specifically in relation to acquired menorrhagia, uterine volume, and expulsion rates.29
Fewer studies have assessed relief of obstructive symptoms or dysmenorrhea.
The beneficial effect of the LNG-IUS on acquired menorrhagia due to a leiomyomatous uterus is well established. In prospective trials, the LNG-IUS has significantly decreased menorrhagia from fibroids, as measured by pictorial blood loss assessment, hemoglobin levels, and blood loss calenders.28
Intrauterine progestin has been compared to ablation in the treatment of menorrhagia in patients with at least one myoma.34
A cohort of women with menorrhagia and a leiomyomatous uterus (<380 g) who declined surgery, were treated with an LNG-IUS. Patients were evaluated at 3, 6 and 12 months and compared to historical controls treated with thermal balloon ablation.34
At 3 months, blood loss was significantly less in the ablation group (P
< 0.0001). By 6 months, however, there was no statistically significant difference in hemoglobin values, pictorial blood loss score or uterine volume between the two groups. These findings persisted at the 12-month examination.34
Not all women with myomas are successfully treated with the LNG-IUS, perhaps because response is determined by the fibroids’ uterine location. In an attempt to identify factors predictive of non response to the LNG-IUS, 44 women presenting for hysterectomy after failed LNG-IUS management for menorrhagia were studied.37
Persistent menorrhagia was the indication for the majority (44 out of 50). Women were retrospectively identified and their pathology reviewed. Examination of the histology demonstrated that the majority of women who failed therapy with an LNG-IUS and fibroids had an abnormal uterus.37
Uterine malformations, such as submucosal fibroids, was the most common finding, although a unicornuate uterus and an LNG-IUS embedded in an old cesarean scar were also noted.38
These specimens showed the expected atrophy, but also contained some areas of persistent endometrial shedding deemed to be consistent with incomplete endometrial suppression.37
Durations of exposure to the LNG-IUS were not specified in the report of this study, which is a chief limitation in assessing the impact of the LNG-IUS.
Studies have evaluated the effect of LNG-IUS on leiomyoma size, but findings have not been consistent. Using sonographic measurements, Grigorieva et al found a significantly decreased uterine volume in LNG-IUS users starting at 3 months after placement and persisting through 12 months.30
They also found a significant decrease in leiomyoma size from 6 months to 12 months of use (30–19 mL, P
= 0.01). A study comparing the effect of LNG-IUS on menorrhagia in women with fibroids and contraceptive users without fibroids also showed a significant decrease in uterine volume over time and between groups.38
Evidence of the outcomes of intrauterine progestin on fibroids comes indirectly from a trial comparing women with a history of breast cancer and receiving tamoxifen. These patients were randomized to endometrial surveillance alone, or insertion of LNG-IUS for prophylaxis of endometrial hyperplasia.39
Sonographic uterine measurements showed that women with the LNG-IUS had decreased endometrial thickness, uterine anterior posterior diameter, uterine cavity length and long diameter. At 1 year of use, endometrial thickness and myoma volume were significantly decreased (P = 0.04).40
A trend towards decrease in size of submucosal fibroids in the LNG-IUS users and a significant increase in the development of fibroids in the control group were also noted.
A 2009 Turkish prospective cohort study assessed the impact of the LNG-IUS on uterine and ovarian volume. At one year of use, endometrial thickness and myoma volume were significantly decreased (P
In contrast, other studies have not shown a significant decrease in uterine volume with an LNG-IUS, despite a consistently significant decrease in blood loss scores.34
These conflicting findings probably reflect study design, specifically length of follow up and inclusion and exclusion criteria. However, it has also been suggested that progesterone may have both stimulatory as well as inhibitory effects on myometrial cells.37
Further research is needed to elucidate the role intrauterine delivery of progestin analogues may play in leiomyoma volume. For the well-counseled patient with menorrhagia secondary to uterine leiomyomas, a trial of the LNG-IUS is supported by the evidence.