How Uterine Fibroids Affect Menstrual Periods
Uterine fibroids commonly cause heavy and prolonged menstrual bleeding, which can lead to anemia, as well as pelvic pain and bulk symptoms that worsen during menstruation. 1
Mechanisms of Fibroid-Related Menstrual Changes
Fibroids affect menstrual periods through several mechanisms:
Abnormal uterine bleeding patterns:
- Heavy menstrual bleeding (menorrhagia)
- Prolonged bleeding episodes
- Irregular bleeding between periods
Underlying mechanisms 2:
- Disruption of normal venous drainage in the uterus
- Enlargement of the uterine cavity surface area
- Abnormal prostaglandin production
- Irregular vascular architecture around fibroids
- Formation of "venous lakes" when fibroids block normal blood flow
- Increased local action of vasoactive growth factors
Types of Fibroids and Their Impact on Menstruation
The location of fibroids significantly affects menstrual symptoms:
Submucosal fibroids (projecting into the uterine cavity):
- Cause the most severe menstrual bleeding
- Most directly interfere with the endometrial lining
- May cause intermenstrual bleeding
Intramural fibroids (within the uterine wall):
- Moderate to severe menstrual bleeding
- May distort the uterine cavity depending on location
Subserosal fibroids (projecting outside the uterus):
- Less likely to affect menstrual bleeding
- More associated with bulk symptoms and pressure
Treatment Options for Fibroid-Related Menstrual Problems
First-Line Medical Management
For patients with fibroid-related heavy menstrual bleeding, first-line treatments include 1:
Non-hormonal options:
- NSAIDs (reduce bleeding by 20-40%)
- Tranexamic acid (effective non-hormonal alternative)
Hormonal options:
- Estrogen-progestin oral contraceptive pills
- Progestin-containing intrauterine devices (IUDs)
- Both effectively reduce bleeding symptoms
Second-Line Medical Management
If first-line treatments fail, consider 1:
GnRH agonists (e.g., leuprolide acetate):
- Significantly reduce bleeding and fibroid volume
- Useful for short-term treatment (3-6 months)
- Can prepare for surgery by reducing fibroid size
- Side effects include hypoestrogenic symptoms (headaches, hot flushes)
Oral GnRH antagonists (e.g., elagolix, linzagolix, relugolix):
- Effective at reducing bleeding and fibroid volume
- Can be combined with low-dose estrogen/progestin to reduce side effects
- FDA-approved for fibroid-related heavy menstrual bleeding
Procedural and Surgical Options
For persistent symptoms despite medical management 1, 3:
Hysteroscopic myomectomy:
- Preferred for submucosal fibroids
- Simple, safe, and effective for heavy menstrual bleeding
- Preserves uterus and fertility
Uterine Artery Embolization (UAE):
- Reduces fibroid size and improves bleeding symptoms
- 82% complete infarction rate
- Reintervention rate of 13% at 2 years
MR-guided Focused Ultrasound (MRgFUS):
- Reduces fibroid diameter by approximately 18%
- Less effective than UAE for symptom control
- Higher reintervention rate (30% vs 13%)
Hysterectomy:
- Definitive treatment that eliminates all fibroid-related symptoms
- Most common treatment for uterine fibroids in the US (75% of cases)
- Only appropriate for women who have completed childbearing
Clinical Pearls and Pitfalls
Important warning signs that require further investigation:
- Postmenopausal bleeding with fibroids
- Rapid growth of fibroids
- Extremely heavy bleeding leading to severe anemia
Monitoring recommendations:
- Follow hemoglobin levels to ensure anemia is resolving
- Monitor fibroid size with imaging (ultrasound) before and after treatment
- Assess symptom improvement based on patient's most relevant symptoms
Treatment selection factors:
- Symptom severity (bleeding vs. pain)
- Patient's age and fertility desires
- Fibroid size, number, and location
- Response to previous treatments
Remember that while many fibroids are asymptomatic and require no intervention, those causing significant menstrual disturbances should be treated promptly to prevent complications like anemia and to improve quality of life.